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.

2006/stewart/README.md

@@ -1,13 +1,13 @@
 ## To build:
 
-```sh
+```<!---sh-->
     make
 ```
 
 
 ## To use:
 
-```sh
+```<!---sh-->
     ./stewart width_and_height iterations file > file.xbm
     convert file.xbm file.png
 ```
@@ -29,7 +29,7 @@ NOTE: `convert(1)` belongs to [ImageMagick](https://imagemagick.org/index.php).
 
 ## Try:
 
-```sh
+```<!---sh-->
     ./try.sh
 ```
 
@@ -58,7 +58,7 @@ a reasonably experienced user who can parse formats in their mind.  :-)
 
 The program should be run with the following
 
-```sh
+```<!---sh-->
     ./stewart <m> <n> <ifs>
 ```
 
@@ -77,7 +77,7 @@ are 3.  Wrong arguments will cause the program to bomb out.
 
 #### Example:
 
-```sh
+```<!---sh-->
     ./stewart 1024 1000000 gasket > gasket.xbm
 ```
 

2006/stewart/index.html

@@ -141,10 +141,10 @@ 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">./stewart</span> width_and_height iterations file <span class="op">&gt;</span> file.xbm</span>
-<span id="cb2-2"><a href="#cb2-2" aria-hidden="true" tabindex="-1"></a>    <span class="ex">convert</span> file.xbm file.png</span></code></pre></div>
+<pre class="&lt;!---sh--&gt;"><code>    ./stewart width_and_height iterations file &gt; file.xbm
+    convert file.xbm file.png</code></pre>
 <p>where <code>file</code> is one of:</p>
 <pre><code>    altar box box2 box3 build carpet circles cross cross2 cross3
     crystal curve diamonds diamonds2 dragon dragon2 dragon3
@@ -154,7 +154,7 @@ Location: <a href="../../location.html#US">US</a> - <em>United States of America
 <p>NOTE: you cannot specify a different width from height; it’s one number.</p>
 <p>NOTE: <code>convert(1)</code> belongs to <a href="https://imagemagick.org/index.php">ImageMagick</a>.</p>
 <h2 id="try">Try:</h2>
-<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">./try.sh</span></span></code></pre></div>
+<pre class="&lt;!---sh--&gt;"><code>    ./try.sh</code></pre>
 <p>After running the program on a few files it will ask you if you wish to run it
 on the remaining files.</p>
 <p>The script will try converting the xbm files created by the program to png
@@ -171,7 +171,7 @@ a reasonably experienced user who can parse formats in their mind. :-)</p>
 <h2 id="authors-remarks">Author’s remarks:</h2>
 <h3 id="execution">Execution</h3>
 <p>The program should be run with the following</p>
-<div class="sourceCode" id="cb5"><pre class="sourceCode sh"><code class="sourceCode bash"><span id="cb5-1"><a href="#cb5-1" aria-hidden="true" tabindex="-1"></a>    <span class="ex">./stewart</span> <span class="op">&lt;</span>m<span class="op">&gt;</span> <span class="op">&lt;</span>n<span class="op">&gt;</span> <span class="op">&lt;</span>ifs<span class="op">&gt;</span></span></code></pre></div>
+<pre class="&lt;!---sh--&gt;"><code>    ./stewart &lt;m&gt; &lt;n&gt; &lt;ifs&gt;</code></pre>
 <p>where:</p>
 <pre><code>    m   = The size of the picture (picture will be m X m in size).
     n   = The number of iterations to run (More will make for a
@@ -181,7 +181,7 @@ a reasonably experienced user who can parse formats in their mind. :-)</p>
 on standard out. Minimal checking is done on the arguments mainly that there
 are 3. Wrong arguments will cause the program to bomb out.</p>
 <h4 id="example">Example:</h4>
-<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">./stewart</span> 1024 1000000 gasket <span class="op">&gt;</span> gasket.xbm</span></code></pre></div>
+<pre class="&lt;!---sh--&gt;"><code>    ./stewart 1024 1000000 gasket &gt; gasket.xbm</code></pre>
 <h3 id="compilationtesting">Compilation/Testing</h3>
 <p>The program compiles without warning with <code>gcc -ansi -Wall</code>.
 <code>lint</code> also seems to like the code. This must be a bug in <code>lint</code>.</p>