Changelog updates (#5967)

* docs: seed 3.0.2 changelog from needs-changelog PRs

Collect suggested entries early to streamline release prep.

* Misc trivial manual fixes.

* Shorten changelog entry for PR 5862

* Remove mention of a minor doc formatting fix.

* Cursor-generated "all past-tense" style

* Restore the meaning of the 5958 entry using the "... now ..." trick, and restore a couple other entries that also use the "now" trick.

* Replace ... now ... style with ... updated to ... style

* [skip ci] docs: group 3.0.2 entries under Internal heading

Align changelog categories with recent releases for review.

* Update changelog with CMake policy compatibility fix

Fix compatibility with CMake policy CMP0190 for cross-compiling.

* Add changelog entries for 5965 and 5968

* docs: make CMP0190 changelog entry past tense

Align 3.0.2 bug-fix entry with changelog style.

* [skip ci] docs: add missing 3.0.2 changelog entries

Capture remaining needs-changelog PRs across categories. (These slipped through the cracks somehow.)

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Co-authored-by: Henry Schreiner <HenrySchreinerIII@gmail.com>