gh-95913: Copyedit/improve Other Language Changes What's New section (#97719)

* Add/refine cross references to items in other lang changes section

* Unify context manager exception changes into single non-repetitive item

* More clearly describe the intent and consequences of the -P option

* Apply minor clarifications & copyedits to rest of section

* Tweak the formatting of module references

Co-authored-by: Ezio Melotti <ezio.melotti@gmail.com>

Co-authored-by: Ezio Melotti <ezio.melotti@gmail.com>