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.

2004/vik1/README.md

@@ -1,20 +1,20 @@
 ## To build:
 
-```sh
+```<!---sh-->
     make
 ```
 
 
 ## To use:
 
-```sh
+```<!---sh-->
     ./vik1 [arg]
 ```
 
 
 ## Try:
 
-```sh
+```<!---sh-->
     ./vik1
 
     ./vik1 a
@@ -82,7 +82,7 @@ Compile the source code and link X libraries if necessary.
 The program takes three options which have to be typed in a specific
 order as described below.
 
-```sh
+```<!---sh-->
     Usage: ./vik1 ['a']['d'][#]
 
     a   - Advanced racing in a winter landscape

2004/vik1/index.html

@@ -141,17 +141,17 @@ 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">./vik1</span> <span class="pp">[</span><span class="ss">arg</span><span class="pp">]</span></span></code></pre></div>
+<pre class="&lt;!---sh--&gt;"><code>    ./vik1 [arg]</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">./vik1</span></span>
-<span id="cb3-2"><a href="#cb3-2" aria-hidden="true" tabindex="-1"></a></span>
-<span id="cb3-3"><a href="#cb3-3" aria-hidden="true" tabindex="-1"></a>    <span class="ex">./vik1</span> a</span>
-<span id="cb3-4"><a href="#cb3-4" aria-hidden="true" tabindex="-1"></a></span>
-<span id="cb3-5"><a href="#cb3-5" aria-hidden="true" tabindex="-1"></a>    <span class="ex">./vik1</span> d2</span>
-<span id="cb3-6"><a href="#cb3-6" aria-hidden="true" tabindex="-1"></a></span>
-<span id="cb3-7"><a href="#cb3-7" aria-hidden="true" tabindex="-1"></a>    <span class="ex">./vik1</span> ad3</span></code></pre></div>
+<pre class="&lt;!---sh--&gt;"><code>    ./vik1
+
+    ./vik1 a
+
+    ./vik1 d2
+
+    ./vik1 ad3</code></pre>
 <p>Can you figure out how to cheat?</p>
 <p>Also see the author’s remarks below for more details on the different
 modes/options.</p>
@@ -184,11 +184,11 @@ glance at the feature list he provided below. Amazing!</p>
 <p>Compile the source code and link X libraries 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">Usage:</span> ./vik1 <span class="pp">[</span><span class="st">&#39;a&#39;</span><span class="pp">][</span><span class="st">&#39;d&#39;</span><span class="pp">][</span><span class="ss">#</span><span class="pp">]</span></span>
-<span id="cb4-2"><a href="#cb4-2" aria-hidden="true" tabindex="-1"></a></span>
-<span id="cb4-3"><a href="#cb4-3" aria-hidden="true" tabindex="-1"></a>    <span class="ex">a</span>   <span class="at">-</span> Advanced racing in a winter landscape</span>
-<span id="cb4-4"><a href="#cb4-4" aria-hidden="true" tabindex="-1"></a>    <span class="ex">d</span>   <span class="at">-</span> Racing in at night in the dark</span>
-<span id="cb4-5"><a href="#cb4-5" aria-hidden="true" tabindex="-1"></a><span class="co">#   - Race track selection 1-3 are valid numbers</span></span></code></pre></div>
+<pre class="&lt;!---sh--&gt;"><code>    Usage: ./vik1 [&#39;a&#39;][&#39;d&#39;][#]
+
+    a   - Advanced racing in a winter landscape
+    d   - Racing in at night in the dark
+#   - Race track selection 1-3 are valid numbers</code></pre>
 <p>Here are a few examples:</p>
 <pre><code>    Command line:               Description: