improve how markdown code language is commented

We added a space between the markdown triple code mark
and language that was enclosed in HTML comments.

So a line of the form:

````
```<!---c--->
````

became:

````
``` <!---c--->
````

This was done to **help** some code see that the HTML comment
string was not a markdown code specifier.   Not all code
understands this after this changed.  For example, `pandoc(1)`
still forms HTML classes of the form "&lt;!---c--&gt;"
when it encounters the above mentioned change.

We also fixed a problem with `2019/dogon/README.md` regarding
a markdown code block.

We also fixed a problem with `2020/yang/README.md` regarding
a markdown code block.

1993/ant/README.md

@@ -1,6 +1,6 @@
 ## To build:
 
-```<!---sh-->
+``` <!---sh-->
     make all
 ```
 
@@ -18,14 +18,14 @@ For more detailed information see [1993 ant bugs](../../bugs.html#1993_ant).
 
 ## To use:
 
-```<!---sh-->
+``` <!---sh-->
     ./ant 'ERE' [file ...]
 ```
 
 
 ## Try:
 
-```<!---sh-->
+``` <!---sh-->
     ./try.sh
 ```
 

1993/cmills/README.md

@@ -4,7 +4,7 @@ We recommend you try the alt version first so you can get a better idea of what
 this entry was like back in 1993. See the [original code](#original-code)
 section below to run the original.
 
-```<!---sh-->
+``` <!---sh-->
     make alt
 ```
 
@@ -16,7 +16,7 @@ requires X11?](../../faq.html#X11macos).
 
 To configure how many microseconds to sleep before updates try:
 
-```<!---sh-->
+``` <!---sh-->
     make clobber SLEEP=200 alt
 ```
 
@@ -34,7 +34,7 @@ For more detailed information see [1993 cmills bugs](../../bugs.html#1993_cmills
 
 ## To use:
 
-```<!---sh-->
+``` <!---sh-->
     DISPLAY="your_X_server_display"
     export DISPLAY
     ./cmills.alt [speed]	# must be run on an X11 server
@@ -56,7 +56,7 @@ on but you can use the original without any delays if you wish.
 
 ### Original build:
 
-```<!---sh-->
+``` <!---sh-->
     make all
 ```
 

1993/dgibson/README.md

@@ -1,13 +1,13 @@
 ## To build:
 
-```<!---sh-->
+``` <!---sh-->
     make all
 ```
 
 
 ## To use:
 
-```<!---sh-->
+``` <!---sh-->
     ./dgibson.sh [datafile]
 ```
 
@@ -18,7 +18,7 @@ where:
 
 ## Try:
 
-```<!---sh-->
+``` <!---sh-->
     ./try.sh
 ```
 

1993/ejb/README.md

@@ -1,26 +1,26 @@
 ## To build:
 
-```<!---sh-->
+``` <!---sh-->
     make all
 ```
 
 
 ## To use:
 
-```<!---sh-->
+``` <!---sh-->
     ./ejb level
 ```
 
 where:
 
-```<!---sh-->
+``` <!---sh-->
     level   a value from -128 to 127
 ```
 
 
 ## Try:
 
-```<!---sh-->
+``` <!---sh-->
     ./try.sh
 ```
 
@@ -45,7 +45,7 @@ We note that this also works under macOS just fine.
 
 #### Output solution to Towers of Hanoi for five rings:
 
-```<!---sh-->
+``` <!---sh-->
     ./ejb 5
 ```
 
@@ -54,7 +54,7 @@ text description of how to solve the puzzle.
 
 #### Output solution to the Patience puzzle for six rings:
 
-```<!---sh-->
+``` <!---sh-->
     ./ejb -6
 ```
 

1993/jonth/README.md

@@ -5,14 +5,14 @@ compile. macOS users running Mountain Lion and later will need to download and
 install [XQuartz](https://www.xquartz.org) in order to compile and run this
 entry.
 
-```<!---sh-->
+``` <!---sh-->
     make all
 ```
 
 
 ## To use:
 
-```<!---sh-->
+``` <!---sh-->
     ./jonth	# must be run on an X11 server
 ```
 

1993/leo/README.md

@@ -1,6 +1,6 @@
 ## To build:
 
-```<!---sh-->
+``` <!---sh-->
     make all
 ```
 
@@ -9,13 +9,13 @@
 
 To have the computer guess:
 
-```<!---sh-->
+``` <!---sh-->
     ./leo [colors]
 ```
 
 To guess the computer's number:
 
-```<!---sh-->
+``` <!---sh-->
     ./mind [colors]
 ```
 

1993/lmfjyh/README.md

@@ -2,7 +2,7 @@
 
 If you have gcc < 2.3.3 you can build this entry like:
 
-```<!---sh-->
+``` <!---sh-->
     make all
 ```
 
@@ -48,7 +48,7 @@ For more detailed information see [1993 lmfjyh bugs](../../bugs.html#1993_lmfjyh
 
 If you have gcc < 2.3.3 (i.e. the entry can compile):
 
-```<!---sh-->
+``` <!---sh-->
     ./lmfjyh
 ```
 
@@ -64,7 +64,7 @@ Nonetheless it will be compiled in case the original entry fails to compile.
 
 Should you wish to build this version manually:
 
-```<!---sh-->
+``` <!---sh-->
     make alt
 ```
 
@@ -99,7 +99,7 @@ that should be familiar to all C-programmers.
 #### Listing 1: A simple "Hello World" program
 
 
-```<!---c-->
+``` <!---c-->
     main()
     {
       puts("Hello World!");
@@ -118,14 +118,14 @@ the file.
 
 #### Listing 2: Compressed "Hello world"
 
-```<!---c-->
+``` <!---c-->
     char*_=__FILE__;
 ```
 
 
 #### Listing 3: Code embedded in the file name
 
-```<!---c-->
+``` <!---c-->
     ";main(){puts("Hello World!");}char*C=".c
 ```
 

1993/plummer/README.md

@@ -1,6 +1,6 @@
 ## To build:
 
-```<!---sh-->
+``` <!---sh-->
     make alt
 ```
 
@@ -12,21 +12,21 @@ code](#original-code) below.
 
 If you wish to speed the entry up, say to 500 microseconds between writes, try:
 
-```<!---sh-->
+``` <!---sh-->
     make clobber SLEEP=500 alt
 ```
 
 Alternatively if you wish to slow it down, say to 1500 microseconds between
 writes, try:
 
-```<!---sh-->
+``` <!---sh-->
     make clobber SLEEP=1500 alt
 ```
 
 
 ## To use:
 
-```<!---sh-->
+``` <!---sh-->
     ./plummer.alt number arg
 ```
 
@@ -42,7 +42,7 @@ bypass](https://hitchhikers.fandom.com/wiki/Bypass).
 
 ## Try:
 
-```<!---sh-->
+``` <!---sh-->
     ./try.alt.sh
 
     ./try.alt.sh 21701
@@ -70,7 +70,7 @@ course).
 
 ### Original build:
 
-```<!---sh-->
+``` <!---sh-->
     make all
 ```
 
@@ -82,7 +82,7 @@ Use `plummer` as you would `plummer.alt` above.
 
 ### Original try:
 
-```<!---sh-->
+``` <!---sh-->
     ./try.sh
 
     ./try.sh 21701

1993/rince/README.md

@@ -1,6 +1,6 @@
 ## To build:
 
-```<!---sh-->
+``` <!---sh-->
     make all
 ```
 
@@ -22,7 +22,7 @@ For more detailed information see [bugs report with 1993/rince](../../bugs.html#
 
 ## To use:
 
-```<!---sh-->
+``` <!---sh-->
     ./rince [cabbage]
 ```
 
@@ -37,13 +37,13 @@ Some people may want to slow down the game by increasing the
 value 17 in the lines:
 
 
-```<!---c-->
+``` <!---c-->
     struct timeval v= {0,1<<17} ;
 ```
 
 and
 
-```<!---c-->
+``` <!---c-->
     refresh(),c=select(k,&y,0,0,(v.tv_usec=1<<17,&v))?getch():0;
 ```
 
@@ -57,7 +57,7 @@ changed).
 
 ### Alternate build:
 
-```<!---sh-->
+``` <!---sh-->
     make SLEEP=18 clobber alt
 ```
 
@@ -107,7 +107,7 @@ with the curses library (typically `/lib/libcurses.a` for static libraries)
 used. It has been suggested that the following gcc command may help:
 
 
-```<!---sh-->
+``` <!---sh-->
     gcc -fno-builtin -I/usr/include -o rince rince.c -lcurses -ltermcap
 ```
 

1993/schnitzi/README.md

@@ -1,6 +1,6 @@
 ## To build:
 
-```<!---sh-->
+``` <!---sh-->
     make all
 ```
 
@@ -18,7 +18,7 @@ For more detailed information see [1993 schnitzi bugs](../../bugs.html#1993_schn
 
 ## To use:
 
-```<!---sh-->
+``` <!---sh-->
     ./schnitzi file
 ```
 
@@ -33,14 +33,14 @@ in [1993 schnitzi bugs](../../bugs.html#1993_schnitzi).
 
 ## Try:
 
-```<!---sh-->
+``` <!---sh-->
     ./schnitzi schnitzi.info
     # ask some questions suggested by the author, noted below
 ```
 
 We also suggest you ask the program the following questions:
 
-```<!---sh-->
+``` <!---sh-->
     Who is Mark Schnitzus?
 
     Who was Jack the Ripper ?
@@ -51,7 +51,7 @@ intentional spelling error there.
 
 Try feeding the program source to the program and ask both:
 
-```<!---sh-->
+``` <!---sh-->
     What is cat ?
     What is cat?
 ```

1993/vanb/README.md

@@ -1,6 +1,6 @@
 ## To build:
 
-```<!---sh-->
+``` <!---sh-->
     make all
 ```
 
@@ -18,7 +18,7 @@ For more detailed information see [1993 vanb bugs](../../bugs.html#1993_vanb).
 
 ## To use:
 
-```<!---sh-->
+``` <!---sh-->
     ./vanb 'exp'
 ```
 
@@ -28,7 +28,7 @@ hexadecimal and decimal numbers.
 
 ## Try:
 
-```<!---sh-->
+``` <!---sh-->
     ./try.sh
 ```
 
@@ -133,7 +133,7 @@ Here's a version of the program before it got formatted into the VIII,
 augmented with comments showing where each state begins. `N1` and `N2` are
 notes:
 
-```<!---c-->
+``` <!---c-->
     #define O5 main
     O5(O2,O7,O3)char**O7;
     {
@@ -180,14 +180,14 @@ printf, and sends the parser to state `012` (which is `<E>`).
 
 The `E` and `T` states work like this:
 
-```<!---c-->
+``` <!---c-->
     int e(){ return eprime( t() ); }
 ```
 
 
 The `E'` and `T'` states work like this:
 
-```<!---c-->
+``` <!---c-->
     int eprime( int intermediate )
     {
 	if( ch == '+' )
@@ -202,7 +202,7 @@ The `E'` and `T'` states work like this:
 The `D`, `X` and `O` states work like this (they assume that they're initially
 called with `0`):
 
-```<!---c-->
+``` <!---c-->
     int octal( int intermediate )
     {
 	if( ch>='0' && ch<='7' )