add hack-a-round for language specified markdown code blocks

When language is specified in a markdown code block such as:

````
```c
    printf("Hello, world!\n");
```
````

is used, the resulting HTML as produced by `pandoc(1)` combined
with our revised `ioccc.css` is not intent the code block well.

A temporary "_hack-a-round_" is to turn the "markdown code language
specifier" into an HTML comment.  For example:

````
```<!---c-->
    printf("Hello, world!\n");
```
````

This commits turns off existing markdown code language specifiers
for now, while preserving our ability to restore them in the future
when a better  "_hack-a-round_" to the "markdown code language
specifier" problem is found.

The HTML impact if this "_hack-a-round_" is to produce HTML that
looks like this:

```
<pre class="&lt;!---c--&gt;"><code> .. </code></pre>
```

We might be able to create a complex set of classes for each markdown
code language (there won't be very many) in `ioccc.css`, or we might
find a more general CSS (or maybe `pandoc(1)`?) solution.

For now, this hack-a-round will have to do.

2005/vik/index.html

@@ -141,11 +141,11 @@ Location: <a href="../../location.html#US">US</a> - <em>United States of America
 <!-- START: this line starts content for HTML phase 21 by: bin/pandoc-wrapper.sh via bin/md2html.sh -->
 
 <h2 id="to-build">To build:</h2>
-<div class="sourceCode" id="cb1"><pre class="sourceCode sh"><code class="sourceCode bash"><span id="cb1-1"><a href="#cb1-1" aria-hidden="true" tabindex="-1"></a>    <span class="fu">make</span></span></code></pre></div>
+<pre class="&lt;!---sh--&gt;"><code>    make</code></pre>
 <h2 id="to-use">To use:</h2>
-<div class="sourceCode" id="cb2"><pre class="sourceCode sh"><code class="sourceCode bash"><span id="cb2-1"><a href="#cb2-1" aria-hidden="true" tabindex="-1"></a>    <span class="ex">./vik</span> <span class="pp">[</span><span class="ss">file.map</span><span class="pp">]</span></span></code></pre></div>
+<pre class="&lt;!---sh--&gt;"><code>    ./vik [file.map]</code></pre>
 <h2 id="try">Try:</h2>
-<div class="sourceCode" id="cb3"><pre class="sourceCode sh"><code class="sourceCode bash"><span id="cb3-1"><a href="#cb3-1" aria-hidden="true" tabindex="-1"></a>    <span class="ex">./vik</span> maze.map</span></code></pre></div>
+<pre class="&lt;!---sh--&gt;"><code>    ./vik maze.map</code></pre>
 <h2 id="judges-remarks">Judges’ remarks:</h2>
 <p>An amazing use of the X libraries with twisty code passages, all different. One
 risks running in code path circles as <code>main()</code> is called again and again. Be
@@ -177,18 +177,18 @@ backward).</li>
 <p>Compile the source code and link in <a href="https://en.wikipedia.org/wiki/Xlib">X
 libraries</a> if necessary. The program takes
 three options which have to be typed in a specific order as described below.</p>
-<div class="sourceCode" id="cb4"><pre class="sourceCode sh"><code class="sourceCode bash"><span id="cb4-1"><a href="#cb4-1" aria-hidden="true" tabindex="-1"></a>    <span class="ex">./vik</span> [-w <span class="op">&lt;</span>width<span class="op">&gt;</span>] <span class="pp">[</span><span class="ss">mapfile</span><span class="pp">]</span></span></code></pre></div>
+<pre class="&lt;!---sh--&gt;"><code>    ./vik [-w &lt;width&gt;] [mapfile]</code></pre>
 <p>where:</p>
 <pre><code>    width   - Specifies the width of the window
     mapfile - Filename containing a map</code></pre>
 <h4 id="examples">Examples</h4>
 <p>Start the engine using a built in labyrinth and texture bitmaps:</p>
-<div class="sourceCode" id="cb6"><pre class="sourceCode sh"><code class="sourceCode bash"><span id="cb6-1"><a href="#cb6-1" aria-hidden="true" tabindex="-1"></a>    <span class="ex">./vik</span></span></code></pre></div>
+<pre class="&lt;!---sh--&gt;"><code>    ./vik</code></pre>
 <p>Start the engine and loads the labyrinth defined in the file
 <a href="maze.map">maze.map</a>:</p>
-<div class="sourceCode" id="cb7"><pre class="sourceCode sh"><code class="sourceCode bash"><span id="cb7-1"><a href="#cb7-1" aria-hidden="true" tabindex="-1"></a>    <span class="ex">./vik</span> maze.map</span></code></pre></div>
+<pre class="&lt;!---sh--&gt;"><code>    ./vik maze.map</code></pre>
 <p>Start the engine using <a href="maze.map">maze.map</a> in a window that is 400 pixels wide:</p>
-<div class="sourceCode" id="cb8"><pre class="sourceCode sh"><code class="sourceCode bash"><span id="cb8-1"><a href="#cb8-1" aria-hidden="true" tabindex="-1"></a>    <span class="ex">./vik</span> <span class="at">-w</span> 400 maze.map</span></code></pre></div>
+<pre class="&lt;!---sh--&gt;"><code>    ./vik -w 400 maze.map</code></pre>
 <p>Note that the <code>mapfile</code> has to be the last argument and the <code>-w</code> option if present
 has to be the first. The map definition files and the bitmap files should be
 located in the current directory.</p>