Add `DiffCleanupSemantic` into the mix when generated diffs (PR review,
commit view and issue/comment history). This avoids trying to produce a
optimal diff and tries to reduce the amount of edits, by combing them
into larger edits, which is nicer and easier to 'look at'. There's no
need for a perfect minimal diff, as the output isn't being parsed by a
computer, it's parsed by people.
Ref: https://codeberg.org/forgejo/forgejo/issues/4996
