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.

1996/jonth/index.html

@@ -141,7 +141,7 @@ Location: <a href="../../location.html#NO">NO</a> - <em>Kingdom of Norway</em> (
 <!-- 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> all</span></code></pre></div>
+<pre class="&lt;!---sh--&gt;"><code>    make all</code></pre>
 <p>NOTE: this entry requires <code>X11/Xlib.h</code> header file and the X11 library to
 compile. macOS users running Mountain Lion and later will need to download and
 install <a href="https://www.xquartz.org">XQuartz</a> in order to compile and run this
@@ -152,17 +152,17 @@ entry.</p>
     STATUS: missing or dead link - please provide them</code></pre>
 <p>For more detailed information see <a href="../../bugs.html#1996_jonth">1996 jonth bugs</a>.</p>
 <h2 id="to-use">To use:</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">./jonth</span> :0 :0</span></code></pre></div>
+<pre class="&lt;!---sh--&gt;"><code>    ./jonth :0 :0</code></pre>
 <p>NOTE: the two boards will be on top of each other so you will have to drag one
 off the other so that you can properly play.</p>
 <p>NOTE: if there is no X service open this will crash. If this is the case you
 might try:</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">./jonth</span></span></code></pre></div>
+<pre class="&lt;!---sh--&gt;"><code>    ./jonth</code></pre>
 <p>These are supposed to happen. As is written in the
 <a href="http://catb.org/jargon/html/F/feature.html">The Jargon File</a>:</p>
 <pre><code>    That&#39;s not a bug, that&#39;s a feature.</code></pre>
 <h2 id="try">Try:</h2>
-<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">./jonth</span> host1:0 host2:0</span></code></pre></div>
+<pre class="&lt;!---sh--&gt;"><code>    ./jonth host1:0 host2:0</code></pre>
 <h2 id="judges-remarks">Judges’ remarks:</h2>
 <p>For extra credit, figure out how you can cheat by taking over a square already
 occupied by an opponent.</p>