[3.12] gh-106969: Indicate no modules were added in 3.10 & 3.12 (GH-106988) (#107094)

The "New Modules" section was left in place to ensure that the anchor
link for new modules will still exist:

/whatsnew/3.12.htmlGH-new-modules
/whatsnew/3.10.htmlGH-new-modules

This means that existing links to this section don't break.
(cherry picked from commit 6dbffaed17d59079d6a2788d686009f762a3278f)

Co-authored-by: Sebastiaan Zeeff <33516116+SebastiaanZ@users.noreply.github.com>