Fixed order of base classes in CBV mixin docs

Thanks carbonXT for the report.

… and error_messages

Refs #20532

…ibility.

…ent-type-test-client

Remove incorrect CONTENT_TYPE header from GET and HEAD requests

…ch patterns were tried.

Thanks to @DrMeers for the report and @ludwigkraatz for the initial patch.

428, 429, 431 and 511

The join used by select_related was incorrectly INNER when the query
had an ORed filter for nullable join that was trimmed away. Fixed this
by forcing the join type to LOUTER even when a join was trimmed away
in ORed queries.

…st suite

Fixed #20598 -- Add new HTTP status codes defined in rfc6585

Fixed #20565 -- Added template examples for GCBV.

By avoiding to run syncdb with the full set of test models.

Thanks Anssi for the idea.

Thanks Chris Lasher for the report.

The _load_library method on BasePasswordHasher turns ImportErrors
into ValueErrors, this masks ImportErrors in the algorithm library.
Changed it to a clearer worded error message that includes
the ImportError string.

Refs #20599.

Thanks batisteo for the report.

There were a couple of places which used Query.join() directly. By
using setup_joins() in these places the code is more DRY, and in
addition there is no need to directly call field.get_joining_columns()
unless the field is the given join_field from get_path_info(). This
makes it easier to make sure a ForeignObject subclass generates joins
correctly in all cases.

Thanks to frog32 for the report and to Tim Graham for the review.

Refs django#18714