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/newbern/README.md

@@ -1,20 +1,20 @@
 ## To build:
 
-```sh
+```<!---sh-->
     make
 ```
 
 
 ## To use:
 
-```sh
+```<!---sh-->
     ./newbern [file.dat arg]
 ```
 
 
 ## Try:
 
-```sh
+```<!---sh-->
     ./try.sh
 ```
 
@@ -34,14 +34,14 @@ This is a configurable `banner(1)`-like program.
 
 - To convert a character glyph into a data file:
 
-```sh
+```<!---sh-->
     ./newbern char < some_nicely_shaped_text >> data_file
 ```
 
 
 - To print a string using glyphs from a data file:
 
-```sh
+```<!---sh-->
     ./newbern data_file a_string
 ```
 

2004/newbern/index.html

@@ -141,11 +141,11 @@ Location: <a href="../../location.html#ZZ">ZZ</a> - <em>Unknown location</em></l
 <!-- 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">./newbern</span> [file.dat arg]</span></code></pre></div>
+<pre class="&lt;!---sh--&gt;"><code>    ./newbern [file.dat 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">./try.sh</span></span></code></pre></div>
+<pre class="&lt;!---sh--&gt;"><code>    ./try.sh</code></pre>
 <h2 id="judges-remarks">Judges’ remarks:</h2>
 <p>The program is formatted using the same font glyphs as the example
 data file.</p>
@@ -155,11 +155,11 @@ data file.</p>
 <ul>
 <li>To convert a character glyph into a data file:</li>
 </ul>
-<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">./newbern</span> char <span class="op">&lt;</span> some_nicely_shaped_text <span class="op">&gt;&gt;</span> data_file</span></code></pre></div>
+<pre class="&lt;!---sh--&gt;"><code>    ./newbern char &lt; some_nicely_shaped_text &gt;&gt; data_file</code></pre>
 <ul>
 <li>To print a string using glyphs from a data file:</li>
 </ul>
-<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">./newbern</span> data_file a_string</span></code></pre></div>
+<pre class="&lt;!---sh--&gt;"><code>    ./newbern data_file a_string</code></pre>
 <h3 id="extra-functionality">Extra functionality</h3>
 <p>The program can also act as a Morse encoder, unarguably.</p>
 <p>It also has double-super-secret encryption capabilities.