gh-95913: Edit zipfile Whatsnew section & add new APIs (GH-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 ed827d56)

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

Doc/whatsnew/3.11.rst

@@ -1110,13 +1110,25 @@ warnings
   providing a more concise way to locally ignore warnings or convert them to errors.
   (Contributed by Zac Hatfield-Dodds in :issue:`47074`.)
 
+
+.. _whatsnew311-zipfile:
+
 zipfile
 -------
 
-* Added support for specifying member name encoding for reading
-  metadata in the zipfile's directory and file headers.
+* Added support for specifying member name encoding for reading metadata
+  in a :class:`~zipfile.ZipFile`'s directory and file headers.
   (Contributed by Stephen J. Turnbull and Serhiy Storchaka in :issue:`28080`.)
 
+* Added :meth:`ZipFile.mkdir() <zipfile.ZipFile.mkdir>`
+  for creating new directories inside ZIP archives.
+  (Contributed by Sam Ezeh in :gh:`49083`.)
+
+* Added :attr:`~zipfile.Path.stem`, :attr:`~zipfile.Path.suffix`
+  and :attr:`~zipfile.Path.suffixes` to :class:`zipfile.Path`.
+  (Contributed by Miguel Brito in :gh:`88261`.)
+
+
 fcntl
 -----