Fixed #21546 -- Strengthened kqueue detection.

Thanks Loic Bistuer.
Fixed 21406 -- Made blocktrans 'trimmed' option preserve line numbers.

Thanks Bouke Haarsma for report, fix and initial patch.
Added link to localized formatting doc from main index.
Migrate prompts if you need makemigrations, runserver prompts for migrate
Add --dry-run option to makemigrations
Add clone() method to Field to get clean copies of it.
Don't make a second migration if there was a force-null-default addcol.
Fixed #21558 -- Support building CHM files.

Thanks Michał Pasternak.
Migration VCS conflict detection and --merge for makemigrations
List 1.6.x releases in descending order
Merge pull request #2029 from alasdairnicol/releases_ordering

List ed 1.6.x releases in descending order