Integrate WHATWG changes into 5.2 (Hijacked) (w3c#747)

* Reflecting a broken URL should return the unparsed value

* Allow currentScript to return SVGScriptElement

* Add MathML and SVG to dependencies and cross reference them correctly

* Resetting a textarea should reset its dirty value flag

* Editorial: formatting changes

* Editorial: formatting fixes

* remove domain to ascii term

* Editorial: Linking and formatting issues

* Add recursion check to frame elements

* Editorial: formatting lines

* Make document.open() and close() check for XML document

* Fix linking error

* Editorial: formatting and linking

* Change data type for HashChageEvent to match reality

* Add missing p tag

* Give more media controls examples

* Editorial: define Event attribute defaults through IDL

* Editorial: clarify the special and ordinary parser categories

* Editorial: linking and formatting

* Make marker of summary inside

* Editorial fixes and linking

* Editorial: synchronize with the DOM Standard

* Editorial: Remove duplicate paragraph

* Editorial: unwrap link

* Editorial: linking fixes and line wrapping

* Make selection members nullable types

* Formalize bogus comment state

* Fix linking errors

sections/semantics-document-metadata.include

@@ -498,8 +498,8 @@
       <var>url</var> and <var>corsAttributeState</var>.
   5. Set <var>request</var>'s <a>client</a> to the <{link}> element's <a>node document</a>'s
       {{Window}} object's <a>environment settings object</a>.
-  6. Set <var>request</var>'s <span>cryptographic
-      nonce metadata</span> to the current state of the <{link}> element's <{link/nonce}> content attribute.	  
+  6. Set <var>request</var>'s <a>cryptographic nonce metadata</a> to the current state of the
+      <{link}> element's <{link/nonce}> content attribute.
   7. <a>Fetch</a> <var>request</var>.
 
   User agents may opt to only try to obtain such resources when they are needed, instead of

sections/semantics-embedded-content.include

@@ -1147,8 +1147,8 @@
 
       <li>&#x231B; <a>Queue a task</a> to change the <a>current request</a>'s <a>current URL</a> to
       the empty string, and then, if the element has a
-      <code>src</code> attribute or it uses <code>srcset</code> or <code>picture</code>, <a>fire a simple
-      event</a> named <code>error</code> at the <{img}>
+      <code>src</code> attribute or it uses <code>srcset</code> or <code>picture</code>,
+      <a>fire a simple event</a> named <code>error</code> at the <{img}>
       element.</li>
 
       <li>&#x231B; Abort this algorithm.</li>
@@ -5480,7 +5480,7 @@ attribute's value is a type that a <a>plugin</a> supports, then the value of the
   (e.g., fullscreen or in an independent resizable window). Captions, subtitles or other additional 
   visual tracks should remain available and visible when enabled. As for the other user interface 
   features, controls to enable this should not interfere with the page's normal rendering unless 
-  the user agent is exposing a user interfaceAs for the other user interface features, controls to 
+  the user agent is exposing a user interface. As for the other user interface features, controls to 
   enable this should not interfere with the page's normal rendering unless the user agent is 
   <a>exposing a user interface</a>. In such an independent context, however, user agents may make 
   full user interfaces visible e.g., play, pause, seeking, and volume controls even if the 

sections/semantics-grouping-content.include

@@ -1570,7 +1570,7 @@
     <dt><a>Categories</a>:</dt>
     <dd>None.</dd>
     <dt><a>Contexts in which this element can be used</a>:</dt>
-    <dd>As a child of a <{figure}> element.</dd>
+    <dd>As a descendant of a <{figure}> element.</dd>
     <dt><a>Content model</a>:</dt>
     <dd><a>Flow content</a>.</dd>
     <dt><a>Tag omission in text/html</a>:</dt>
@@ -1588,7 +1588,7 @@
   </dl>
 
   The <{figcaption}> element <a>represents</a> a caption or legend for the rest of the
-  contents of the <{figcaption}> element's nearest ancestor <{figure}> element, if any.
+  contents of the <{figcaption}> element's parent <{figure}> element, if any.
 
 <h4 id="the-main-element">The <dfn element><code>main</code></dfn> element</h4>
   <dl class="element">