Fixed flake8 warnings.
Fixed #13163 -- Added ability to show change links on inline objects in admin.

Thanks DrMeers for the suggestion.
Fixed #16383 -- Raised the AttributeError raised in property of an object when used in a template.

Thanks maraujop for the report and Hiroki and Tim Graham for review.
Updated timezone docs to use timezone.now()

Thanks James Cleveland for the report and Aymeric for suggesting
the solution.
Fixed #22956 -- Made PermissionManager.get_by_natural_key() use the correct database for content type lookup.
Used JsonResponse in CBV examples.

Thanks Hiroki Kiyohara and Tim Graham for the reviews.
Fixed #22808 -- Made ModelMultipleChoiceField validation more robust to invalid data types..

Thanks Mattias Lindvall for the report and inital patch.
Replaced django-admin.py with django-admin in the man page.