Known failure page (#1876)

This PR adds a known failures page. This resolves #1750.

The known failures are moved from the example pages.
(I also updated all example pages with invalid HTML.)

Some known failures were actually fixed in the meantime but never updated, so I removed a few. Those were: 
- Handlebars
- Markdown's nested bold-italic
- Smarty
- Textile's "Nested styles are only partially supported"

### Screenshot

<details>

![image](https://user-images.githubusercontent.com/20878432/56849438-7eca3200-68f4-11e9-9dc3-bf0256be8d1e.png)

</details>

examples/prism-actionscript.html

@@ -93,7 +93,7 @@ <h2>Full example</h2>
       var gradientBmp:BitmapData = new BitmapData(256, 10, false, 0);
       gradientBmp.draw(gradient);
       RLUT = new Array(); GLUT = new Array(); BLUT = new Array();
-      for (var i:int = 0; i < 256; i++) {
+      for (var i:int = 0; i &lt; 256; i++) {
         var pixelColor:uint = gradientBmp.getPixel(i, 0);
         //I drew the gradient backwards, so sue me
         RLUT[256-i] = pixelColor & 0xff0000;
@@ -130,4 +130,4 @@ <h2>Full example</h2>
       colorBmp.paletteMap(sourceBmp, sourceBmp.rect, O, RLUT, GLUT, BLUT, null);
     }
   }
-}</code></pre>
+}</code></pre>

examples/prism-applescript.html

@@ -24,18 +24,3 @@ <h2>Classes and units</h2>
 set averageTemp to 63 as degrees Fahrenheit
 set circleArea to (pi * 7 * 7) as square yards
 </code></pre>
-
-<h2>Known failures</h2>
-<p>There are certain edge cases where Prism will fail.
-	There are always such cases in every regex-based syntax highlighter.
-	However, Prism dares to be open and honest about them.
-	If a failure is listed here, it doesn’t mean it will never be fixed. This is more of a “known bugs” list, just with a certain type of bug.
-</p>
-
-<h3>Comments only support one level of nesting</h3>
-<pre><code>(* Nested block
-	(* comments
-		(* on more than
-		2 levels *)
-	are *)
-not supported *)</code></pre>

examples/prism-arduino.html

@@ -14,7 +14,7 @@ <h2>Booleans</h2>
 false;</code></pre>
 
 <h2>Operators</h2>
-<pre><code>a < b;
+<pre><code>a &lt; b;
 c &amp;&amp; d;</code></pre>
 
 <h2>Full example</h2>
@@ -28,7 +28,7 @@ <h2>Full example</h2>
  * runs once before everyhing else
  */
 void setup() {
-    pinMode(piezo, OUTPUT);     
+    pinMode(piezo, OUTPUT);
 }
 
 /**

examples/prism-asciidoc.html

@@ -88,7 +88,7 @@ <h2>Tables</h2>
 <pre><code>[cols="e,m,^,>s",width="25%"]
 |============================
 |1 >s|2 |3 |4
-^|5 2.2+^.^|6 .3+<.>m|7
+^|5 2.2+^.^|6 .3+&lt;.>m|7
 ^|8
 |9 2+>|10
 |============================</code></pre>
@@ -101,4 +101,4 @@ <h2>Inline styles</h2>
 <h2>Attribute entries</h2>
 <pre><code>:Author Initials: JB
 {authorinitials}
-:Author Initials!:</code></pre>
+:Author Initials!:</code></pre>

examples/prism-aspnet.html

@@ -1,36 +1,36 @@
 <h2>Comments</h2>
-<pre><code><%-- This is a comment --%>
-<%-- This is a
+<pre><code>&lt;%-- This is a comment --%>
+&lt;%-- This is a
 multi-line comment --%></code></pre>
 
 <h2>Page directives</h2>
-<pre><code><%@ Page Title="Products" Language="C#" MasterPageFile="~/Site.Master" AutoEventWireup="true"  CodeBehind="ProductList.aspx.cs" Inherits="WingtipToys.ProductList" %>
+<pre><code>&lt;%@ Page Title="Products" Language="C#" MasterPageFile="~/Site.Master" AutoEventWireup="true"  CodeBehind="ProductList.aspx.cs" Inherits="WingtipToys.ProductList" %>
 </code></pre>
 
 <h2>Directive tag</h2>
-<pre><code><%: Page.Title %>
-&lt;a href="ProductDetails.aspx?productID=<%#:Item.ProductID%>">
+<pre><code>&lt;%: Page.Title %>
+&lt;a href="ProductDetails.aspx?productID=&lt;%#:Item.ProductID%>">
 &lt;span>
-    <%#:Item.ProductName%>
+	&lt;%#:Item.ProductName%>
 &lt;/span></code></pre>
 
 <h2>Highlighted C# inside scripts</h2>
 <p>This requires the C# component to be loaded.
 	On this page, check C# <strong>before</strong> checking ASP.NET should make
 	the example below work properly.</p>
 <pre><code>&lt;script runat="server">
-    // The following variables are visible to all procedures
-    // within the script block.
-    String str;
-    int i;
-    int i2;
+	// The following variables are visible to all procedures
+	// within the script block.
+	String str;
+	int i;
+	int i2;
 
-    int DoubleIt(int inpt)
-    {
-        // The following variable is visible only within
-        // the DoubleIt procedure.
-        int factor = 2;
+	int DoubleIt(int inpt)
+	{
+		// The following variable is visible only within
+		// the DoubleIt procedure.
+		int factor = 2;
 
-        return inpt * factor;
-    }
-&lt;/script></code></pre>
+		return inpt * factor;
+	}
+&lt;/script></code></pre>

examples/prism-autohotkey.html

@@ -19,7 +19,7 @@ <h2>Full example</h2>
     return
 if f_class = #32770    ; It's a dialog.
 {
-    if f_Edit1Pos <>   ; And it has an Edit1 control.
+    if f_Edit1Pos &lt;>   ; And it has an Edit1 control.
     {
         ; Activate the window so that if the user is middle-clicking
         ; outside the dialog, subsequent clicks will also work:
@@ -37,7 +37,7 @@ <h2>Full example</h2>
 }
 else if f_class in ExploreWClass,CabinetWClass  ; In Explorer, switch folders.
 {
-    if f_Edit1Pos <>   ; And it has an Edit1 control.
+    if f_Edit1Pos &lt;>   ; And it has an Edit1 control.
     {
         ControlSetText, Edit1, %f_path%, ahk_id %f_window_id%
         ; Tekl reported the following: "If I want to change to Folder L:\folder
@@ -65,4 +65,4 @@ <h2>Full example</h2>
 ; 2) It's a supported type but it lacks an Edit1 control to facilitate the custom
 ;    action, so instead do the default action below.
 Run, Explorer %f_path%  ; Might work on more systems without double quotes.
-return</code></pre>
+return</code></pre>

examples/prism-autoit.html

@@ -36,17 +36,3 @@ <h2>Keywords and variables</h2>
     EndIf
     MsgBox($MB_SYSTEMMODAL, "", "The value of $i is: " & $i)
 Next</code></pre>
-
-<h2>Known failures</h2>
-<p>There are certain edge cases where Prism will fail.
-	There are always such cases in every regex-based syntax highlighter.
-	However, Prism dares to be open and honest about them.
-	If a failure is listed here, it doesn’t mean it will never be fixed. This is more of a “known bugs” list, just with a certain type of bug.
-</p>
-
-<h3>Nested block comments</h3>
-<pre><code>#cs
-	#cs
-		foo()
-	#ce
-#ce</code></pre>

examples/prism-bash.html

@@ -21,7 +21,7 @@ <h2>Variables</h2>
 echo ${args[0]} ${args[1]} ${args[2]}</code></pre>
 
 <h2>Keywords</h2>
-<pre><code>for (( i=0;i<$ELEMENTS;i++)); do
+<pre><code>for (( i=0;i&lt;$ELEMENTS;i++)); do
 	echo ${ARRAY[${i}]}
 done
 while read LINE; do
@@ -46,4 +46,4 @@ <h2>Some well-known commands</h2>
 
 git pull origin master
 
-sudo gpg --refresh-keys; sudo apt-key update; sudo rm -rf /var/lib/apt/{lists,lists.old}; sudo mkdir -p /var/lib/apt/lists/partial; sudo apt-get clean all; sudo apt-get update</code></pre>
+sudo gpg --refresh-keys; sudo apt-key update; sudo rm -rf /var/lib/apt/{lists,lists.old}; sudo mkdir -p /var/lib/apt/lists/partial; sudo apt-get clean all; sudo apt-get update</code></pre>

examples/prism-basic.html

@@ -57,7 +57,7 @@ <h2>QuickBASIC example</h2>
    CALL PrintSomeStars(NumStars)
    DO
       INPUT "Do you want more stars? ", Answer$
-   LOOP UNTIL Answer$ <> ""
+   LOOP UNTIL Answer$ &lt;> ""
    Answer$ = LEFT$(Answer$, 1)
 LOOP WHILE UCASE$(Answer$) = "Y"
 PRINT "Goodbye "; UserName$
@@ -66,4 +66,4 @@ <h2>QuickBASIC example</h2>
    REM This procedure uses a local variable called Stars$
    Stars$ = STRING$(StarCount, "*")
    PRINT Stars$
-END SUB</code></pre>
+END SUB</code></pre>

examples/prism-bison.html

@@ -50,7 +50,7 @@ <h2>Full example</h2>
   string*	op_val;
 }
 
-%start	input 
+%start	input
 
 %token	&lt;int_val>	INTEGER_LITERAL
 %type	&lt;int_val>	exp
@@ -74,7 +74,7 @@ <h2>Full example</h2>
 {
   extern int yylineno;	// defined and maintained in lex.c
   extern char *yytext;	// defined and maintained in lex.c
-  
+
   cerr &lt;&lt; "ERROR: " &lt;&lt; s &lt;&lt; " at symbol \"" &lt;&lt; yytext;
   cerr &lt;&lt; "\" on line " &lt;&lt; yylineno &lt;&lt; endl;
   exit(1);
@@ -84,21 +84,3 @@ <h2>Full example</h2>
 {
   return yyerror(string(s));
 }</code></pre>
-
-<h2>Known failures</h2>
-<p>There are certain edge cases where Prism will fail.
-	There are always such cases in every regex-based syntax highlighter.
-	However, Prism dares to be open and honest about them.
-	If a failure is listed here, it doesn’t mean it will never be fixed. This is more of a “known bugs” list, just with a certain type of bug.
-</p>
-
-<h3>Two levels of nesting inside C section</h3>
-<pre><code>{
-	if($1) {
-		if($2) {
-
-		}
-	}
-} // <- Broken
-%%
-%%</code></pre>

examples/prism-brainfuck.html

@@ -7,15 +7,15 @@ <h2>Full example</h2>
         >+++            Add 3 to Cell #3
         >+++            Add 3 to Cell #4
         >+              Add 1 to Cell #5
-        <<<<-           Decrement the loop counter in Cell #1
+        &lt;&lt;&lt;&lt;-           Decrement the loop counter in Cell #1
     ]                   Loop till Cell #1 is zero; number of iterations is 4
     >+                  Add 1 to Cell #2
     >+                  Add 1 to Cell #3
     >-                  Subtract 1 from Cell #4
     >>+                 Add 1 to Cell #6
-    [<]                 Move back to the first zero cell you find; this will
+    [&lt;]                 Move back to the first zero cell you find; this will
                         be Cell #1 which was cleared by the previous loop
-    <-                  Decrement the loop Counter in Cell #0
+    &lt;-                  Decrement the loop Counter in Cell #0
 ]                       Loop till Cell #0 is zero; number of iterations is 8
 
 The result of this is:
@@ -27,11 +27,11 @@ <h2>Full example</h2>
 >---.                   Subtract 3 from Cell #3 to get 101 which is 'e'
 +++++++..+++.           Likewise for 'llo' from Cell #3
 >>.                     Cell #5 is 32 for the space
-<-.                     Subtract 1 from Cell #4 for 87 to give a 'W'
-<.                      Cell #3 was set to 'o' from the end of 'Hello'
+&lt;-.                     Subtract 1 from Cell #4 for 87 to give a 'W'
+&lt;.                      Cell #3 was set to 'o' from the end of 'Hello'
 +++.------.--------.    Cell #3 for 'rl' and 'd'
 >>+.                    Add 1 to Cell #5 gives us an exclamation point
 >++.                    And finally a newline from Cell #6</code></pre>
 
 <h2>One-line example</h2>
-<pre><code>++++++++[>++++[>++>+++>+++>+<<<<-]>+>+>->>+[<]<-]>>.>---.+++++++..+++.>>.<-.<.+++.------.--------.>>+.>++.</code></pre>
+<pre><code>++++++++[>++++[>++>+++>+++>+&lt;&lt;&lt;&lt;-]>+>+>->>+[&lt;]&lt;-]>>.>---.+++++++..+++.>>.&lt;-.&lt;.+++.------.--------.>>+.>++.</code></pre>

examples/prism-bro.html

@@ -300,7 +300,7 @@ <h2>Full example</h2>
 	# because c might not correspond to an active connection (which
 	# causes the function to fail).
 	if ( suppress_UDP_scan_checks &&
-	     service >= 0/udp && service <= 65535/udp )
+	     service >= 0/udp && service &lt;= 65535/udp )
 		return F;
 
 	if ( service in skip_services && ! outbound )
@@ -343,8 +343,8 @@ <h2>Full example</h2>
 					empty_bs_table;
 				}
 
-			if ( ++distinct_backscatter_peers[orig][resp] <= 2 &&
-			     # The test is <= 2 because we get two check_scan()
+			if ( ++distinct_backscatter_peers[orig][resp] &lt;= 2 &&
+			     # The test is &lt;= 2 because we get two check_scan()
 			     # calls, once on connection attempt and once on
 			     # tear-down.
 
@@ -380,7 +380,7 @@ <h2>Full example</h2>
 					pre_distinct_peers[orig] = set();
 
 				add pre_distinct_peers[orig][resp];
-				if ( |pre_distinct_peers[orig]| < addr_scan_trigger )
+				if ( |pre_distinct_peers[orig]| &lt; addr_scan_trigger )
 					ignore = T;
 				}
 
@@ -462,7 +462,7 @@ <h2>Full example</h2>
 		}
 
 	# Check for low ports.
-	if ( activate_priv_port_check && ! outbound && service < 1024/tcp &&
+	if ( activate_priv_port_check && ! outbound && service &lt; 1024/tcp &&
 	     service !in troll_skip_service )
 		{
 		if ( orig !in distinct_low_ports ||
@@ -559,7 +559,7 @@ <h2>Full example</h2>
 		return F;
 		}
 
-	if ( idx[orig] <= |v| && n >= v[idx[orig]] )
+	if ( idx[orig] &lt;= |v| && n >= v[idx[orig]] )
 		{
 		++idx[orig];
 		return T;
@@ -578,7 +578,7 @@ <h2>Full example</h2>
 		return F;
 		}
 
-	if ( idx[orig,resp] <= |v| && n >= v[idx[orig, resp]] )
+	if ( idx[orig,resp] &lt;= |v| && n >= v[idx[orig, resp]] )
 		{
 		++idx[orig,resp];
 		return T;
@@ -642,4 +642,4 @@ <h2>Full example</h2>
 	for ( orig in distinct_low_ports )
 		lowport_summary(distinct_low_ports, orig);
 	}
-</code></pre>
+</code></pre>

examples/prism-c.html

@@ -16,7 +16,7 @@ <h2>Full example</h2>
 {
    int c;
    printf("Number of command line arguments passed: %d\n", argc);
-   for ( c = 0 ; c < argc ; c++)
+   for ( c = 0 ; c &lt; argc ; c++)
       printf("%d. Command line argument passed is %s\n", c+1, argv[c]);
    return 0;
-}</code></pre>
+}</code></pre>

examples/prism-clojure.html

@@ -255,8 +255,8 @@ <h2>Full example</h2>
 
 ; The "Thread-first" macro (->) inserts into each form the result of
 ; the previous, as the first argument (second item)
-(->  
-   {:a 1 :b 2} 
+(->
+   {:a 1 :b 2}
    (assoc :c 3) ;=> (assoc {:a 1 :b 2} :c 3)
    (dissoc :b)) ;=> (dissoc (assoc {:a 1 :b 2} :c 3) :b)
 
@@ -275,7 +275,7 @@ <h2>Full example</h2>
                  ; Result: [1 3 5 7 9]
 
 ; When you are in a situation where you want more freedom as where to
-; put the result of previous data transformations in an 
+; put the result of previous data transformations in an
 ; expression, you can use the as-> macro. With it, you can assign a
 ; specific name to transformations' output and use it as a
 ; placeholder in your chained expressions:
@@ -365,7 +365,7 @@ <h2>Full example</h2>
 (swap! my-atom assoc :b 2) ; Sets my-atom to the result of (assoc {:a 1} :b 2)
 
 ; Use '@' to dereference the atom and get the value
-my-atom  ;=> Atom<#...> (Returns the Atom object)
+my-atom  ;=> Atom&lt;#...> (Returns the Atom object)
 @my-atom ; => {:a 1 :b 2}
 
 ; Here's a simple counter using an atom
@@ -383,4 +383,4 @@ <h2>Full example</h2>
 
 ; Other STM constructs are refs and agents.
 ; Refs: http://clojure.org/refs
-; Agents: http://clojure.org/agents</code></pre>
+; Agents: http://clojure.org/agents</code></pre>