Removed a mention of `Form._errors` from the documentation.

Also removed a sentence that was incorrect: raising a
`ValidationError` inside `Form.clean` doesn't clear the
`cleaned_data` attribute.

Thanks to loic84 and timograham for the review.
Fixed typos in previous commit (9aa6d4bdb6618ba4f17acc7b7c0d1462d6cbc718).
Fixed #21410 -- prefetch_related() for ForeignKeys with related_name='+'

Regression introduced by commit 9777442.

Thanks to trac username troygrosfield for the report and test case.
Added release note for #21410; thanks Loic.
Release notes for ORM changes in 1.6
Propagate get_user_model exception from get_user

Fixes #21439
Merge pull request #1920 from mattrobenolt/unboundlocalerror

Fixed #21439 -- Propagated get_user_model exception from get_user
Fixed #21432 -- DateTimeQuery now copies tzinfo when cloning.

Thanks Enrique Martínez for the report and @bmispelon for the tests.
Added backported fixes to 1.6.1 release notes.
Fixed typo and slightly improved error message when db is missing time zone definitions.

Refs #21432.
Fixed #21440 -- Typo in topics/http/shortcuts.txt

Thanks olof.bjarnason at gmail.com for the report.
Merge pull request #1921 from loic/ticket21432

Fixed typo and slightly improved error message when db is missing time zone definitions.
Fixed the use of the -ise suffix, where -ize is prefered
Fixed #21425 -- Made order in which loggers are introduced consistent.

Thanks oubiga for the suggestion.
Clarified MySQL Connector note.
Configure settings sooner in makemessages

As get_text_list is using translations, setup settings before
calling it.
Fixed #21415 -- Replaced escape sequence by literal non-breaking space

Unfortunately, escape sequences (\x.. or \u....) do not fit well
with the gettext toolchain. Falling back to using literal char,
even if visibility is not ideal.
Fixed #21440 -- Typo #2 in topics/http/shortcuts.txt

Thanks alasdair.
Fixed #21447 -- Restored code erroneously removed in 20472aa827669d2b83b74e521504e88e18d086a1.

Also added some tests for HttpRequest.__repr__.
Note that the added tests don't actually catch the accidental code
removal (see ticket) but they do cover a codepath that wasn't tested
before.

Thanks to Tom Christie for the report and the original patch.
Moved import at proper place in contrib.sites