PEP 771: Amendments following pre-publish discussion (#4238)

Co-authored-by: Adam Turner <9087854+AA-Turner@users.noreply.github.com>
Co-authored-by: Carol Willing <carolcode@willingconsulting.com>
Co-authored-by: Pradyun Gedam <pradyunsg@gmail.com>
Co-authored-by: Hugo van Kemenade <1324225+hugovk@users.noreply.github.com>