Fixed #21942 -- Moved Form.clean() to form API docs.

Thanks cjerdonek for the suggestion.
Fixed #19489 -- Documented host parameter of assertRedirects().

Thanks mrknacky at gmail.com for the report and gajimenezmaggiora
for the draft patch.
Made docs CSS for versionchanged/added more similar to docs.djangoproject.com.
Fixed #22482 -- Recommended using data migrations in contrib.sites docs.

Thanks scibi for the report.
Fixed non-multiple of 4 indentation in docs/ref/request-response.txt.
Fixed #14334 -- Query relation lookups now check object types.

Thanks rpbarlow for the suggestion; and loic, akaariai, and jorgecarleitao
for reviews.
Fixed #22691 -- Added aliasing to cached_property.
Removed django/contrib/auth/create_superuser.py

It's a shim that calls the actual createsuperuser management command and
it's been marked as deprecated since Django 1.0.
Fixed #19501 -- added Model.from_db() method

The Model.from_db() is intended to be used in cases where customization
of model loading is needed. Reasons can be performance, or adding custom
behavior to the model (for example "dirty field tracking" to issue
automatic update_fields when saving models).

A big thank you to Tim Graham for the review!
Included irc link in paragraph to allow for l10n

Translators may want to change the irc link pointing to a
language-specific channel.
Fixed #22933 -- Deprecated django.template.resolve_variable().
Fixed #13755 -- Added a tip for caching responses that vary on AJAX.

Thanks mila for the suggestion.
Fixed #22932: Documented circular dependency issues with swappable user
Removed non-existent reference to args/kwargs in manager docs.
assertEquals -> assertEqual
Clarified that LocMemCache is per-process; refs #7639.

Thanks projectgus for the suggestion.
Removed ADMIN_FOR from global_settings.py.

The functionality it was used for was removed in Django 1.7.
Fixed #22940 -- Added missing string iterpolation parameters in migrations.writer error.

Forwardport of f5740af868 from stable/1.7.x
Fixed #22935 -- Changed ForeignKey.default_error_messages['invalid'] to refer to correct field.

Thanks Tim Graham for suggestion and review.
Fixed #18108 -- Added instructions for translating documentation.

Thanks Claude Paroz.