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.

2001/rosten/README.md

@@ -1,6 +1,6 @@
 ## To build:
 
-```sh
+```<!---sh-->
     make
 ```
 
@@ -18,7 +18,7 @@ For more detailed information see [2001 rosten bugs](../../bugs.html#2001_rosten
 
 ## To use:
 
-```sh
+```<!---sh-->
     ./rosten [number]
 ```
 
@@ -30,14 +30,14 @@ NOTE: number is floating point.
 
 ## Try:
 
-```sh
+```<!---sh-->
     ./rosten 1.03
     ./rosten 1.00
 ```
 
 For some abuse, try:
 
-```sh
+```<!---sh-->
     ./rosten 0.99
 ```
 
@@ -57,7 +57,7 @@ cursor) in the wrong way.  :-)
 
 ### SYNOPSIS
 
-```sh
+```<!---sh-->
     ./rosten [greasiness]
 ```
 
@@ -94,7 +94,7 @@ portable, but compile with almost no warnings on most of the compilers
 tested. It's a kind of shame that none of the compilers do anything
 like this:
 
-```sh
+```<!---sh-->
     $ make greasymouse
     cc greasymouse.c -o greasymouse -lX11
     greasymouse.c:30: This macro should have more text and spaces in it
@@ -142,7 +142,7 @@ the way it's used to.
 The MIPS compiler suggests an `==` instead of an `=` in expressions
 such as:
 
-```c
+```<!---c-->
     &&(a=b)
 ```