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.

2020/ferguson1/COMPILING.html

@@ -146,7 +146,7 @@ matters; I only have Intel CPUs and arm64 (MacBook Pro M1).</p>
 <p>I imagine that it works for 32-bit systems but I do not know for sure.</p>
 <h1 id="portability-macos">Portability: macOS</h1>
 <p>You should be able to get the compiler with:</p>
-<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">sudo</span> xcode-select <span class="at">--install</span></span></code></pre></div>
+<pre class="&lt;!---sh--&gt;"><code>    sudo xcode-select --install</code></pre>
 <p>You don’t need Xcode itself and it appears that the command line tools (as above
 should install) already has ncurses so there shouldn’t be anything else that
 needs to be done. But I’m not actually sure of this - I’m seeing conflicting
@@ -159,20 +159,20 @@ so that you don’t need sudo because … Well never mind.</p>
 you want to use the Makefile) to compile and link this entry. With Fedora more
 recent versions there’s the <code>dnf</code> package manager but I cannot help with any of
 the GUI installers since I don’t use them. Something like:</p>
-<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="fu">sudo</span> dnf install ncurses-devel ncurses make gcc</span></code></pre></div>
+<pre class="&lt;!---sh--&gt;"><code>    sudo dnf install ncurses-devel ncurses make gcc</code></pre>
 <p>or</p>
-<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="co"># dnf install ncurses-devel ncurses make gcc</span></span></code></pre></div>
+<pre class="&lt;!---sh--&gt;"><code>    # dnf install ncurses-devel ncurses make gcc</code></pre>
 <h1 id="portability-centos">Portability: CentOS</h1>
 <p>Just like Fedora you will need <code>gcc</code>, <code>ncurses</code>, <code>ncurses-devel</code> (and if you
 want to use the Makefile <code>make</code>). CentOS uses <code>yum</code> and CentOS 8 uses <code>dnf</code>.
 So:</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="fu">sudo</span> yum install ncurses-devel ncurses make gcc</span></code></pre></div>
+<pre class="&lt;!---sh--&gt;"><code>    sudo yum install ncurses-devel ncurses make gcc</code></pre>
 <p>or</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="co"># yum install ncurses-devel ncurses make gcc</span></span></code></pre></div>
+<pre class="&lt;!---sh--&gt;"><code>    # yum install ncurses-devel ncurses make gcc</code></pre>
 <p>or</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="fu">sudo</span> dnf install ncurses-devel ncurses make gcc</span></code></pre></div>
+<pre class="&lt;!---sh--&gt;"><code>    sudo dnf install ncurses-devel ncurses make gcc</code></pre>
 <p>or</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="co"># dnf install ncurses-devel ncurses make gcc</span></span></code></pre></div>
+<pre class="&lt;!---sh--&gt;"><code>    # dnf install ncurses-devel ncurses make gcc</code></pre>
 <p>You can also use clang to compile (which is what gcc actually is under macOS).</p>
 <h1 id="compilation-notes">Compilation notes</h1>
 <p>As long as you have the dependencies above the only thing that comes to mind is