enable syntax highlighting for inline code (#17585)

* enable syntax highlighting for inline code

* finish '.. default-role' and preliminary '.. role'

implementation

* more compact check in dirRole

* set :literal: as default role for *.rst

* Update lib/packages/docutils/rst.nim

Co-authored-by: Timothee Cour <timothee.cour2@gmail.com>

* use whichRole for setting currRoleKind

* Update lib/packages/docutils/rst.nim

Co-authored-by: Timothee Cour <timothee.cour2@gmail.com>

* rename rnGeneralRole -> rnUnknownRole

Co-authored-by: Timothee Cour <timothee.cour2@gmail.com>

nimdoc/rst2html/expected/rst_examples.html

@@ -213,7 +213,7 @@ stmt = IND{>} stmt ^+ IND{=} DED  # list of statements
 </dl>
 <p>Let <tt class="docutils literal"><span class="pre">T</span></tt>'s be <tt class="docutils literal"><span class="pre">p</span></tt>'s return type. NRVO applies for <tt class="docutils literal"><span class="pre">T</span></tt> if <tt class="docutils literal"><span class="pre">sizeof(T) &gt;= N</span></tt> (where <tt class="docutils literal"><span class="pre">N</span></tt> is implementation dependent), in other words, it applies for &quot;big&quot; structures.</p>
 <p>Apart from built-in operations like array indexing, memory allocation, etc. the <tt class="docutils literal"><span class="pre">raise</span></tt> statement is the only way to raise an exception.</p>
-<p><tt class="docutils literal"><span class="pre">typedesc</span></tt> used as a parameter type also introduces an implicit generic. <tt class="docutils literal"><span class="pre">typedesc</span></tt> has its own set of rules:</p>
+<p><tt class="docutils literal"><span class="pre"><span class="Identifier">typedesc</span></span></tt> used as a parameter type also introduces an implicit generic. <tt class="docutils literal"><span class="pre"><span class="Identifier">typedesc</span></span></tt> has its own set of rules:</p>
 <p>The <tt class="docutils literal"><span class="pre">!=</span></tt>, <tt class="docutils literal"><span class="pre">&gt;</span></tt>, <tt class="docutils literal"><span class="pre">&gt;=</span></tt>, <tt class="docutils literal"><span class="pre">in</span></tt>, <tt class="docutils literal"><span class="pre">notin</span></tt>, <tt class="docutils literal"><span class="pre">isnot</span></tt> operators are in fact templates:</p>
 <p><tt class="docutils literal"><span class="pre">a &gt; b</span></tt> is transformed into <tt class="docutils literal"><span class="pre">b &lt; a</span></tt>.<br/><tt class="docutils literal"><span class="pre">a in b</span></tt> is transformed into <tt class="docutils literal"><span class="pre">contains(b, a)</span></tt>.<br/><tt class="docutils literal"><span class="pre">notin</span></tt> and <tt class="docutils literal"><span class="pre">isnot</span></tt> have the obvious meanings.<br/></p><p>A template where every parameter is <tt class="docutils literal"><span class="pre">untyped</span></tt> is called an <span id="immediate_1">immediate</span> template. For historical reasons templates can be explicitly annotated with an <tt class="docutils literal"><span class="pre">immediate</span></tt> pragma and then these templates do not take part in overloading resolution and the parameters' types are <em>ignored</em> by the compiler. Explicit immediate templates are now deprecated.</p>
 
@@ -297,10 +297,10 @@ stmt = IND{&gt;} stmt ^+ IND{=} DED  # list of statements
 <h1><a class="toc-backref" id="introduction" href="#introduction">Introduction</a></h1><blockquote><p>
 "Der Mensch ist doch ein Augentier -- sch&ouml;ne Dinge w&uuml;nsch ich mir."
 </p></blockquote><p>This document is a tutorial for the programming language <em>Nim</em>. This tutorial assumes that you are familiar with basic programming concepts like variables, types, or statements but is kept very basic. The <a class="reference external" href="manual.html">manual</a> contains many more examples of the advanced language features. All code examples in this tutorial, as well as the ones found in the rest of Nim's documentation, follow the <a class="reference external" href="nep1.html">Nim style guide</a>.</p>
-<p>However, this does not work. The problem is that the procedure should not only <tt class="docutils literal"><span class="pre">return</span></tt>, but return and <strong>continue</strong> after an iteration has finished. This <em>return and continue</em> is called a <tt class="docutils literal"><span class="pre">yield</span></tt> statement. Now the only thing left to do is to replace the <tt class="docutils literal"><span class="pre">proc</span></tt> keyword by <tt class="docutils literal"><span class="pre">iterator</span></tt> and here it is - our first iterator:</p>
+<p>However, this does not work. The problem is that the procedure should not only <tt class="docutils literal"><span class="pre">return</span></tt>, but return and <strong>continue</strong> after an iteration has finished. This <em>return and continue</em> is called a <tt class="docutils literal"><span class="pre"><span class="Keyword">yield</span></span></tt> statement. Now the only thing left to do is to replace the <tt class="docutils literal"><span class="pre">proc</span></tt> keyword by <tt class="docutils literal"><span class="pre">iterator</span></tt> and here it is - our first iterator:</p>
 <table border="1" class="docutils"><tr><th>A1 header</th><th>A2 | not fooled</th></tr>
 <tr><td>C1</td><td>C2 <strong>bold</strong></td></tr>
-<tr><td>D1 <tt class="docutils literal"><span class="pre">code \|</span></tt></td><td>D2</td></tr>
+<tr><td>D1 <tt class="docutils literal"><span class="pre"><span class="Identifier">code</span> <span class="Operator">\|</span></span></tt></td><td>D2</td></tr>
 <tr><td>E1 | text</td><td></td></tr>
 <tr><td></td><td>F2 without pipe</td></tr>
 </table><p>not in table </p>

nimdoc/rst2html/source/rst_examples.rst

@@ -5,6 +5,10 @@ Not a Nim Manual
 :Authors: Andreas Rumpf, Zahary Karadjov
 :Version: |nimversion|
 
+.. role:: nim(code)
+   :language: nim
+.. default-role:: nim
+
 .. contents::