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.

news.html

@@ -206,8 +206,8 @@ in <em>date(1)</em> format.</p>
 <a href="status.json">status.json</a> page,
 a <em>“latest_news”</em> JSON member whose value is the date
 of the most recent news item.</p>
-<div class="sourceCode" id="cb2"><pre class="sourceCode json"><code class="sourceCode json"><span id="cb2-1"><a href="#cb2-1" aria-hidden="true" tabindex="-1"></a>    <span class="er">&quot;status_date&quot;</span> <span class="er">:</span> <span class="er">&quot;Mon</span> <span class="er">Jan</span> <span class="er">30</span> <span class="er">02:28:44</span> <span class="er">PST</span> <span class="er">2023&quot;,</span></span>
-<span id="cb2-2"><a href="#cb2-2" aria-hidden="true" tabindex="-1"></a>    <span class="er">&quot;latest_news&quot;</span> <span class="er">:</span> <span class="er">&quot;Mon</span> <span class="er">Jan</span> <span class="er">30</span> <span class="er">02:28:44</span> <span class="er">PST</span> <span class="er">2023&quot;</span></span></code></pre></div>
+<pre class="&lt;!---json--&gt;"><code>    &quot;status_date&quot; : &quot;Mon Jan 30 02:28:44 PST 2023&quot;,
+    &quot;latest_news&quot; : &quot;Mon Jan 30 02:28:44 PST 2023&quot;</code></pre>
 <h1 id="section-3">2022-12-18</h1>
 <p>As per the suggestion of <a href="https://fosstodon.org/@Virtaava@home.social">Toni Mikkola</a>
 (_<span class="citation" data-cites="Virtaava">@Virtaava</span><span class="citation" data-cites="home.social_">@home.social_</span>) we now maintain a