Improve markdown guidelines wording

Amongst the changes here is that we do not need to have the hex or html
code (numbers) for open and close parentheses (in links) as there are
names. '(' is & followed by lpar; and the ')' is the same but 'rpar;'
instead. This makes it easier to remember and type and it generates the
same html as well (they are all valid). Now the markdown files are
consistent in this (in some cases hex was used and in others the html
code).

Although many markdown files were updated no html files needed to be
updated as it generates the same html. Even so I ran the appropriate
rules to do so just to verify this.

1989/jar.2/README.md

@@ -32,7 +32,7 @@ NOTE: this entry will likely segfault on invalid input.
 
 This is the most useful program submitted this year. It is a
 rather large subset of
-[lisp](https://en.wikipedia.org/wiki/Lisp_(programming_language)).
+[lisp](https://en.wikipedia.org/wiki/Lisp_(programming_language)).
 It has no error recovery, and performs rather poorly in a number of cases.  Even
 so, placing all this functionality in such a small, densely packed program, is
 impressive enough to win the `Best of Show` award.

1989/robison/README.md

@@ -56,7 +56,7 @@ For an interesting document on APL, see
 
 This program is a handy picoAPL interpreter written in `C--`.  It
 outputs the evaluation of an
-[APL](https://en.wikipedia.org/wiki/APL_(programming_language)) expression from standard
+[APL](https://en.wikipedia.org/wiki/APL_(programming_language)) expression from standard
 input.  Functions are limited to dyadic `+`,`-`,`x`, and unary `-`;
 numerals must be binary.  Parentheses may be used for
 grouping.  For example: