revamp of portions of perlre

I have finally finished a long-planned in back-burner folding of the 
after-thought section of perlre that describes Version 8 regexes.  I 
have folded this in, mainly to a new Basics, section at the beginning of 
the document.  It is now located, with some other doc changes, at

https://perl5.git.perl.org/perl.git/shortlog/refs/heads/khw/doc

if you have comments

• revamp of portions of perlre by Karl Williamson
• Re: revamp of portions of perlre by Sawyer X
• Re: revamp of portions of perlre by Aaron Crane