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.

1984/anonymous/README.md

@@ -1,13 +1,13 @@
 ## To build:
 
-```<!---sh-->
+``` <!---sh-->
     make all
 ```
 
 
 ## To use:
 
-```<!---sh-->
+``` <!---sh-->
     ./anonymous
 ```
 
@@ -22,7 +22,7 @@ as the alternate code. See below for the tattoo side-by-side with the code.
 
 ### Alternate build:
 
-```<!---sh-->
+``` <!---sh-->
     make alt
 ```
 
@@ -31,7 +31,7 @@ as the alternate code. See below for the tattoo side-by-side with the code.
 
 NOTE: this version might not work on some systems like macOS.
 
-```<!---sh-->
+``` <!---sh-->
     ./anonymous.alt
 ```
 

1984/decot/README.md

@@ -1,6 +1,6 @@
 ## To build:
 
-```<!---sh-->
+``` <!---sh-->
     make all
 ```
 
@@ -22,7 +22,7 @@ For more detailed information see [1984 decot bugs](../../bugs.html#1984_decot).
 
 ## To use:
 
-```<!---sh-->
+``` <!---sh-->
     ./decot
 ```
 
@@ -36,14 +36,14 @@ can use this version.
 
 ### Alternate build:
 
-```<!---sh-->
+``` <!---sh-->
     make alt
 ```
 
 
 ### Alternate use:
 
-```<!---sh-->
+``` <!---sh-->
     ./decot.alt
 ```
 
@@ -61,13 +61,13 @@ the judges offer this one comment: understand remarks!
 Some new (in 1984) compilers disliked line 15 of the original source, so we
 changed it from:
 
-```<!---c-->
+``` <!---c-->
     for(signal=0;*k * x * __FILE__ *i;) do {
 ```
 
 to:
 
-```<!---c-->
+``` <!---c-->
     for(signal=0;*k *x * __FILE__ *i;) do {
 ```
 
@@ -75,7 +75,7 @@ To see what we mean look at the [original source file](decot.orig.c). The
 [alternate code](decot.alt.c) is the version that has this modification. The
 fixed version has instead:
 
-```<!---c-->
+``` <!---c-->
     for(signal=0;*k *= * __FILE__ *i;) do {
 ```
 

1984/laman/README.md

@@ -1,13 +1,13 @@
 ## To build:
 
-```<!---sh-->
+``` <!---sh-->
     make all
 ```
 
 
 ## To use:
 
-```<!---sh-->
+``` <!---sh-->
     ./laman <positive number>
 ```
 
@@ -17,7 +17,7 @@
 The program accepts ONE POSITIVE number.  Seeing is believing, so try things
 like:
 
-```<!---sh-->
+``` <!---sh-->
     ./try.sh
 
     ./laman 4
@@ -33,14 +33,14 @@ This code should run you in circles.
 Some new compilers (in 1984) dislike lines 6 and 10 of the source, so we changed
 them from:
 
-```<!---c-->
+``` <!---c-->
     ;++f)a[		b<<5|c]		=d++,b+		=e;for(		f=0;f<O
     <<5|c]^		=a[b<<5		|c]^=a[		(k-(b+1		))<<5|c]
 ```
 
 to:
 
-```<!---c-->
+``` <!---c-->
     ;++f)a[		b<<5|c]		=d++,b+=	e;for(		f=0;f<O
     <<5|c]^=	a[b<<5		|c]^=a[		(k-(b+1		))<<5|c]
 ```

1984/mullender/README.md

@@ -1,6 +1,6 @@
 ## To build:
 
-```<!---sh-->
+``` <!---sh-->
     make alt
 ```
 
@@ -24,7 +24,7 @@ For more detailed information see [1984 mullender bugs](../../bugs.html#1984_mul
 
 ## To use:
 
-```<!---sh-->
+``` <!---sh-->
     ./mullender.alt [microseconds]
 ```
 
@@ -48,7 +48,7 @@ which is probably not as uncommon as you think :-).
 
 ## Try:
 
-```<!---sh-->
+``` <!---sh-->
     ./mullender.alt
 
     ./mullender.alt 5000	# wait for 5000 microseconds and see what happens
@@ -72,14 +72,14 @@ machine dependent code was discouraged.
 
 ### Original build:
 
-```<!---sh-->
+``` <!---sh-->
     make all
 ```
 
 
 ### Original use:
 
-```<!---sh-->
+``` <!---sh-->
     ./mullender
 ```
 
@@ -137,19 +137,19 @@ Repo](https://github.com/dspinellis/unix-history-repo/tree/Research-Release).
 `gentab.c` can be built like:
 
 
-```<!---sh-->
+``` <!---sh-->
     make gentab
 ```
 
 ### gentab use:
 
-```<!---sh-->
+``` <!---sh-->
     ./gentab file
 ```
 
 ### gentab try:
 
-```<!---sh-->
+``` <!---sh-->
     ./gentab gentab > g.c
 ```
 
@@ -256,7 +256,7 @@ separate.
 The [PDP](https://en.wikipedia.org/wiki/Programmed_Data_Processor) and
 [VAX](https://en.wikipedia.org/wiki/VAX) codes implement the same algorithm:
 
-```<!---c-->
+``` <!---c-->
     for (;;) {
 	write(1, "  :-)\b\b\b\b", 9);
 	delay();
@@ -284,7 +284,7 @@ We started with writing the
 We both knew [PDP-11](https://en.wikipedia.org/wiki/PDP-11) assembly so that was
 no problem. The assembly code we came up with is as follows:
 
-```<!---asm-->
+``` <!---asm-->
     pdp:
 	mov pc,r4
 	tst -(r4)
@@ -331,7 +331,7 @@ VAX code in C and massaged the
 program that we came up with is as follows:
 
 
-```<!---asm-->
+``` <!---asm-->
     vax: .word 0400 + (pdp - vax) / 2 - 1
     1:
 	pushl $9
@@ -389,7 +389,7 @@ extracted the machine code from the object file.
 > NOTE from judges: see [gentab.c](gentab.c) for a copy of this file that can be
 compiled in modern systems.
 
-```<!---c-->
+``` <!---c-->
     #include <stdio.h>
     #include <a.out.h>