[3.12] gh-109190: What's New in 3.12: Add subheadings to removals for easy linking (GH-109159) (#109273)

gh-109190: What's New in 3.12: Add subheadings to removals for easy linking (GH-109159)
(cherry picked from commit 57b6205523d934d61b6308d63ef72c494c7d2b7e)

Co-authored-by: Hugo van Kemenade <hugovk@users.noreply.github.com>
Co-authored-by: Adam Turner <9087854+AA-Turner@users.noreply.github.com>