[perl #74642] DOC PATCH: various fixes to pods

# New Ticket Created by  karl williamson 
# Please include the string:  [perl #74642]
# in the subject line of all future correspondence about this issue. 
# <URL: http://rt.perl.org/rt3/Ticket/Display.html?id=74642 >


These are mostly about regex and Unicode things, and correcting a couple 
broken links.  Details in the commit messages

• [perl #74642] DOC PATCH: various fixes to pods by Rafael Garcia-Suarez via RT
• [perl #74642] DOC PATCH: various fixes to pods by karl williamson