Markdown.pl: improve readability of a few regexs
treed5da2801ff2b492efd3160337173f53dbf7e83a6
-rw-r--r-- 1526 LICENSE
-rwxr-xr-x 175323 Markdown.pl
lrwxrwxrwx 11 Markdown.pm -> Markdown.pl
-rw-r--r-- 17596 README
lrwxrwxrwx 6 README.md -> README
-rw-r--r-- 9672 basics.md
-rw-r--r-- 50580 syntax.md