[3.12] GH-109190: Copyedit 3.12 What's New: Improve the C-API deprecations section...

[3.12] GH-109190: Copyedit 3.12 What's New: Improve the C-API deprecations section (GH-109751) (#109830)

* GH-109190: Copyedit 3.12 What's New: Improve the C-API deprecations section (GH-109751)
(cherry picked from commit bccc1b78002c924e8f4121fea5de7df5eb127548)

Co-authored-by: Adam Turner <9087854+AA-Turner@users.noreply.github.com>
Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>
* Remove the weakref get object functions

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Co-authored-by: Adam Turner <9087854+AA-Turner@users.noreply.github.com>
Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>