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/jdalbec/README.md

@@ -1,6 +1,6 @@
 ## To build:
 
-```sh
+```<!---sh-->
     make
 ```
 
@@ -21,14 +21,14 @@ For more detailed information see [2004 jdalbec bugs](../../bugs.html#2004_jdalb
 
 ## To use:
 
-```sh
+```<!---sh-->
     ./jdalbec number ...
 ```
 
 
 ## Try:
 
-```sh
+```<!---sh-->
     ./try.sh
 ```
 
@@ -43,7 +43,7 @@ which line it is on.
 
 ### Alternate build:
 
-```sh
+```<!---sh-->
     make alt
 ```
 
@@ -52,7 +52,7 @@ many number of lines to print on a line. Set at default to 11 protons, salt, if
 you wish to make it silver, 47 (a prime) protons, do:
 
 
-```sh
+```<!---sh-->
     make clobber Ag=47 alt
 ```
 
@@ -60,7 +60,7 @@ though it might be odd to have 47 numbers on a line as it would defeat the
 purpose. :-) Or if you prefer some prime, golden irony:
 
 
-```sh
+```<!---sh-->
     make clobber Ag=79 alt
 ```
 
@@ -72,7 +72,7 @@ Use `jdalbec.alt` as you would `jdalbec` above.
 
 ### Alternate try:
 
-```sh
+```<!---sh-->
     ./try.alt.sh
 ```