[1.5.x] Added dates to release notes.
[1.5.x] Bumped version number post-release.
[1.5.x] Fixed spelling mistake in file docs.

Backport of a3e88e64a4 from master
Fixed #23329 -- Allowed inherited and m2m fields to be referenced in the admin.

Thanks to Trac alias Markush2010 and ross for the detailed reports.

Backport of 3cbb759 from master
[1.5.x] Fixed #23375 -- Added missing security issues to the archive.

Backport of c9c0be3 from master
[1.5.x] Bump version numbers for bugfix release.
Merged 1.5.10 django update with bulk_insert branch
Merge tag '1.5.10' of https://github.com/django/django into bulk_insert-return-IDs

Tag 1.5.10