[Markdown] Refactor fenced code blocks (sublimehq#2925)

* [Markdown] Sort fenced codeblock contexts alphabetically

This commit just sorts embedded syntaxes by alphabetically language tag.

* [Markdown] Add Diff/Patch syntax to fenced code blocks

* [Markdown] Add Haskell syntax to fenced code blocks

* [Markdown] Add JSX syntax to fenced code blocks

* [Markdown] Add Lisp syntax to fenced code blocks

* [Markdown] Add Lua syntax to fenced code blocks

* [Markdown] Add Matlab syntax to fenced code blocks

* [Markdown] Add OCaml syntax to fenced code blocks

* [Markdown] Add Scala syntax to fenced code blocks

* [Markdown] Add TSX syntax to fenced code blocks

* [Markdown] Add HTML syntax to fenced code blocks

* [Markdown] Fix HTML+PHP completion details

* [Markdown] Reorganize fenced codeblock syntaxes

Create a dedicated context for each syntax in case someone wants to address them in an inherited Markdown syntax.

* [Markdown] Reorganize fenced codeblocks

This commit splits `raw` context into `code-span` and `code-block`.
The ladder is called `fenced-code-blocks`, finally.

The reasons are:

1. `raw` is used in `inline` context, which is also used within link
   texts and other inline-only places which never contain code-blocks.
   By only matching fenced codeblocks when they are likely to appear
   parsing duration of syntax test file is reduced by about 10%.

2. Several duplicated explicit matches are replaced by including the new
   `fenced-code-blocks` context.

The dedicated `fenced-syntaxes` context excludes `fenced-raw` in order
to make it easier for inherited syntaxes to append further contexts.

* [Markdown] Add dedicated fenced-raw-content context

To reduce number of anonymous contexts and improve inherit-ability

* [Markdown] Fix thematic break after fenced codeblocks

Fixes sublimehq#2947

Fenced codeblocks are a separate type of block, which must not be part
of ordinary paragraphs.

see: https://spec.commonmark.org/0.30/#leaf-blocks

* [Markdown] Simplify regexp language pattern

* [Markdown] Add support for fenced `shell` language tag

Markdown/Code Block Syntaxes.sublime-completions

@@ -55,6 +55,12 @@
 			"kind": ["markup", "s", "Syntax"],
 			"details": "Specifies <code>C#</code> code highlighting"
 		},
+		{
+			"trigger": "diff",
+			"annotation": "Diff",
+			"kind": ["markup", "s", "Syntax"],
+			"details": "Specifies <code>Diff</code> code highlighting"
+		},
 		{
 			"trigger": "erlang",
 			"annotation": "Erlang",
@@ -79,11 +85,23 @@
 			"kind": ["markup", "s", "Syntax"],
 			"details": "Specifies <code>GraphViz</code> code highlighting"
 		},
+		{
+			"trigger": "haskell",
+			"annotation": "Haskell",
+			"kind": ["markup", "s", "Syntax"],
+			"details": "Specifies <code>Haskell</code> code highlighting"
+		},
+		{
+			"trigger": "html",
+			"annotation": "HTML",
+			"kind": ["markup", "s", "Syntax"],
+			"details": "Specifies <code>HTML</code> code highlighting"
+		},
 		{
 			"trigger": "html+php",
 			"annotation": "PHP",
 			"kind": ["markup", "s", "Syntax"],
-			"details": "Specifies <code>PHP</code> code highlighting"
+			"details": "Specifies <code>HTML+PHP</code> code highlighting"
 		},
 		{
 			"trigger": "inc",
@@ -133,6 +151,30 @@
 			"kind": ["markup", "s", "Syntax"],
 			"details": "Specifies <code>Java Server Pages</code> code highlighting"
 		},
+		{
+			"trigger": "JSX",
+			"annotation": "JavaScript React",
+			"kind": ["markup", "s", "Syntax"],
+			"details": "Specifies <code>JavaScript React</code> code highlighting"
+		},
+		{
+			"trigger": "lisp",
+			"annotation": "Lisp",
+			"kind": ["markup", "s", "Syntax"],
+			"details": "Specifies <code>Lisp</code> code highlighting"
+		},
+		{
+			"trigger": "lua",
+			"annotation": "Lua",
+			"kind": ["markup", "s", "Syntax"],
+			"details": "Specifies <code>Lua</code> code highlighting"
+		},
+		{
+			"trigger": "matlab",
+			"annotation": "MatLab",
+			"kind": ["markup", "s", "Syntax"],
+			"details": "Specifies <code>MatLab</code> code highlighting"
+		},
 		{
 			"trigger": "obj-c",
 			"annotation": "Objective-C",
@@ -181,6 +223,18 @@
 			"kind": ["markup", "s", "Syntax"],
 			"details": "Specifies <code>Objective-C++</code> code highlighting"
 		},
+		{
+			"trigger": "ocaml",
+			"annotation": "OCaml",
+			"kind": ["markup", "s", "Syntax"],
+			"details": "Specifies <code>OCaml</code> code highlighting"
+		},
+		{
+			"trigger": "patch",
+			"annotation": "Patch",
+			"kind": ["markup", "s", "Syntax"],
+			"details": "Specifies <code>Patch</code> code highlighting"
+		},
 		{
 			"trigger": "perl",
 			"annotation": "Perl 5",
@@ -259,12 +313,24 @@
 			"kind": ["markup", "s", "Syntax"],
 			"details": "Specifies <code>Rust</code> code highlighting"
 		},
+		{
+			"trigger": "scala",
+			"annotation": "Scala",
+			"kind": ["markup", "s", "Syntax"],
+			"details": "Specifies <code>Scala</code> code highlighting"
+		},
 		{
 			"trigger": "sh",
 			"annotation": "ShellScript",
 			"kind": ["markup", "s", "Syntax"],
 			"details": "Specifies <code>ShellScript</code> code highlighting"
 		},
+		{
+			"trigger": "shell",
+			"annotation": "ShellScript",
+			"kind": ["markup", "s", "Syntax"],
+			"details": "Specifies <code>ShellScript</code> code highlighting"
+		},
 		{
 			"trigger": "shell-script",
 			"annotation": "ShellScript",
@@ -289,6 +355,12 @@
 			"kind": ["markup", "s", "Syntax"],
 			"details": "Specifies <code>TypeScript</code> code highlighting"
 		},
+		{
+			"trigger": "tsx",
+			"annotation": "TypeScript React",
+			"kind": ["markup", "s", "Syntax"],
+			"details": "Specifies <code>TypeScript React</code> code highlighting"
+		},
 		{
 			"trigger": "typescript",
 			"annotation": "TypeScript",