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.

2013/birken/README.md

@@ -529,7 +529,7 @@ origin of each file is detailed below (character, game, company, year).
 
 * [belmont.txt](belmont.txt) - [Simon
 Belmont](https://en.wikipedia.org/wiki/Simon_Belmont),
-[Castlevania](https://en.wikipedia.org/wiki/Castlevania_(1986_video_game)),
+[Castlevania](https://en.wikipedia.org/wiki/Castlevania_(1986_video_game)),
 [Konami](https://en.wikipedia.org/wiki/Konami), 1986.
 
 * [bloober.txt](bloober.txt) - Bloober, [Super Mario
@@ -573,7 +573,7 @@ Plant](https://www.mariowiki.com/Piranha_Plant), Super Mario Brothers, Nintendo,
 
 * [samus.txt](samus.txt) - [Samus
 Aran](https://metroid.fandom.com/wiki/Samus_Aran),
-[Metroid](https://metroid.fandom.com/wiki/Metroid_(game)), Nintendo/[Intelligent
+[Metroid](https://metroid.fandom.com/wiki/Metroid_(game)), Nintendo/[Intelligent
 Systems](https://en.wikipedia.org/wiki/Intelligent_Systems), 1986.
 
 * [toad.txt](toad.txt) - [Toad](https://www.mariowiki.com/Toad), Super Mario

2013/hou/README.md

@@ -61,7 +61,7 @@ really just a decompressor to generate the real source code of the
 program.
 
 This program will loop infinitely while progressively refining a
-[raytraced](https://en.wikipedia.org/wiki/Ray_tracing_(graphics)) image.
+[raytraced](https://en.wikipedia.org/wiki/Ray_tracing_(graphics)) image.
 
 NOTE: the author refers to `a.c`, placed in a gzipped file `a.c.gz`. We do not
 include it but it can be generated like: