[3.11] gh-95913: Edit zipfile Whatsnew section & add new APIs (GH-98314) by miss-islington · Pull Request #98430 · python/cpython

…H-98314)

* Link ZipFile in What's New entry discussing it

* Add entry for new ZipFile.mkdir method

* Add entry for new zipfile.Path.stem/suffix/suffixes methods

* Add missing line breaks between zipfile bullet list items
(cherry picked from commit ed827d5)

Co-authored-by: C.A.M. Gerlach <CAM.Gerlach@Gerlach.CAM>