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.

1986/applin/README.md

@@ -1,20 +1,20 @@
 ## To build:
 
-```<!---sh-->
+``` <!---sh-->
     make all
 ```
 
 
 ## To use:
 
-```<!---sh-->
+``` <!---sh-->
     ./applin
 ```
 
 
 ## Try:
 
-```<!---sh-->
+``` <!---sh-->
     ./applin.c
 ```
 

1986/august/README.md

@@ -1,6 +1,6 @@
 ## To build:
 
-```<!---sh-->
+``` <!---sh-->
     make all
 ```
 
@@ -18,7 +18,7 @@ For more detailed information see [1986 august bugs](../../bugs.html#1986_august
 
 ## Try:
 
-```<!---sh-->
+``` <!---sh-->
     ./august
 ```
 

1986/bright/README.md

@@ -1,20 +1,20 @@
 ## To build:
 
-```<!---sh-->
+``` <!---sh-->
     make all
 ```
 
 
 ## To use:
 
-```<!---sh-->
+``` <!---sh-->
     ./bright some_file
 ```
 
 
 ## Try:
 
-```<!---sh-->
+``` <!---sh-->
     ./try.sh
 ```
 

1986/hague/README.md

@@ -1,13 +1,13 @@
 ## To build:
 
-```<!---sh-->
+``` <!---sh-->
     make all
 ```
 
 
 ## To use:
 
-```<!---sh-->
+``` <!---sh-->
     ./hague 2>/dev/null
     # enter some text
 ```
@@ -15,7 +15,7 @@
 
 ## Try:
 
-```<!---sh-->
+``` <!---sh-->
     ./try.sh
 ```
 

1986/holloway/README.md

@@ -1,13 +1,13 @@
 ## To build:
 
-```<!---sh-->
+``` <!---sh-->
     make all
 ```
 
 
 ## Try:
 
-```<!---sh-->
+``` <!---sh-->
     ./holloway
 ```
 

1986/marshall/README.md

@@ -1,6 +1,6 @@
 ## To build:
 
-```<!---sh-->
+``` <!---sh-->
     make all
 ```
 
@@ -18,7 +18,7 @@ if nothing else.
 
 ## To use:
 
-```<!---sh-->
+``` <!---sh-->
     ./marshall
 ```
 
@@ -36,14 +36,14 @@ instead offer the problematic code as an alternate version whereas
 To see if your compiler has the problems noted:
 
 
-```<!---sh-->
+``` <!---sh-->
     make alt
 ```
 
 
 ### Alternate use:
 
-```<!---sh-->
+``` <!---sh-->
     ./marshall.alt
 ```
 

1986/marshall/compilers.md

@@ -54,7 +54,7 @@ dumps core just like before!  What about the call to `_exit()`?
 The call was:
 
 
-```<!---c-->
+``` <!---c-->
     _exit(argv[(int)*argc-2/cc[1*(int)*argc]|-1<<4]);
 ```
 
@@ -72,7 +72,7 @@ infinite loop!
 After we fix the infinite loop if we change the `_exit()` call in macOS and
 disable the optimiser we might get something like:
 
-```<!---sh-->
+``` <!---sh-->
     $ ./marshall
 	  choo choo
     Segmentation fault: 11

1986/pawka/README.md

@@ -1,13 +1,13 @@
 ## To build:
 
-```<!---sh-->
+``` <!---sh-->
     make all
 ```
 
 
 ## Try:
 
-```<!---sh-->
+``` <!---sh-->
     ./pawka
 ```
 

1986/stein/README.md

@@ -1,13 +1,13 @@
 ## To build:
 
-```<!---sh-->
+``` <!---sh-->
     make all
 ```
 
 
 ## To use:
 
-```<!---sh-->
+``` <!---sh-->
     ./stein $(printf "\015\015"); echo
 ```
 
@@ -24,7 +24,7 @@ The `\015` in the above `printf(1)` command produces a control-N.
 One some machines, a control-M control-N arg is needed
 to get the command to output cleanly:
 
-```<!---sh-->
+``` <!---sh-->
     ./stein $(printf "\014\015"); echo
 ```
 

1986/wall/README.md

@@ -1,13 +1,13 @@
 ## To build:
 
-```<!---sh-->
+``` <!---sh-->
     make all
 ```
 
 
 ## To use:
 
-```<!---sh-->
+``` <!---sh-->
     ./wall
 ```