[1.6.x] Fixed #23343 -- Typo in docs/ref/class-based-views/generic-date-based.txt.

Backport of 14aff0bd82 from master
[1.6.x] Fixed #23342 -- Clarified warning about naive time objects.

Thanks to apollo13 for suggested wording.

Backport of b7336ec179 from master
[1.6.x] Fixed #23324 -- Mentioned Site.id in contrib.sites docs.

Backport of a76aab3583 from master