Fixes to thanks for fixes file

At least one entry was missing (1984/anonymous).

Some entries were removed. One such entry was not ever broken but
instead when I had renamed a file (to markdown) I forgot to update the
DATA variable in the Makefile which then broke compilation. This was
seen in the log and mistakenly believed that there was something wrong
with the entry when there wasn't. Other entries removed were not fixes
but notes.

Various README.md files have been updated for this sometimes just
formatting merely because I opened the file because for instance there
is an alternate version (many by me) that is referred to. I'd not be
surprised if more README.md files have to be updated for this much
better system but these will be found in time when I do another pass
(and some years I have not checked at all yet).

1987/wall/README.md

@@ -62,10 +62,10 @@ quit # for the cat version
 
 What we found amazing was how the flow of control was transferred
 between subroutines.  Careful inspection will show that the array of
-pointers to functions named 'vi' refers to functions which seem to not
+pointers to functions named `vi` refers to functions which seem to not
 be directly called.  Even so, these pointers to functions are being
-used as an argument to signal.  Can you determine why this is being
-done and how it is being exploited?
+used as an argument to `signal()` (used both with and without an arg - but
+how?).  Can you determine why this is being done and how it is being exploited?
 
 Some compilers complained about this file, so we changed: `=++I` to `= ++I`.