[1.6.x] 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.

Backport of 9aa6d4bdb6618ba4f17acc7b7c0d1462d6cbc718 and
0048ed77c7016a03aed6dbc255a6372f3df2ccd5 from master.
[1.6.x] 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.

Backpatch of cb83448891f2920c926f61826d8eae4051a3d8f2 from master.

Conflicts:

	tests/prefetch_related/models.py
[1.6.x] Added release note for #21410; thanks Loic.

Backport of 94d567ba30 from master
[1.6.x] Release notes for ORM changes in 1.6

Backport of 4301d6fa36 from master
[1.6.x] Propagate get_user_model exception from get_user

Fixes #21439

Backport of 3560ef04 from master.

Conflicts:
	django/contrib/auth/tests/test_auth_backends.py
[1.6.x] Fixed #21432 -- DateTimeQuery now copies tzinfo when cloning.

Thanks Enrique Martínez for the report and @bmispelon for the tests.

Backport of 17ed99f3a3eea4bd27fa34be59c3582616ed8079 from master.
Fixed wrong override_settings path introduced by 67c30426c1370f5d6c39bd73888c3902c1c5f365.
[1.6.x] Added backported fixes to 1.6.1 release notes.

Backport of 8e6d1b97921dd3ead6afd5eb39fcd2c82244e106 from master.
Fixed Python2.6 incompatibility caused by 67c30426c1370f5d6c39bd73888c3902c1c5f365.
[1.6.x] Fixed #21440 -- Typo in topics/http/shortcuts.txt

Thanks olof.bjarnason at gmail.com for the report.

Backport of 6e9e6ca071 from master
[1.6.x] 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.

Backport of 7e0ebd74c from master.
[1.6.x] Updated humanize translation catalog

Refs #21415
[1.6.x] Fixed #21440 -- Typo #2 in topics/http/shortcuts.txt

Thanks alasdair.

Backport of d011714002 from master
[1.6.x] Fixed #21428 -- editable GenericRelation regression

The GenericRelation refactoring removed GenericRelations from
model._meta.many_to_many. This had the side effect of disallowing
editable GenericRelations in ModelForms. Editable GenericRelations
aren't officially supported, but if we don't fix this we don't offer any
upgrade path for those who used the ability to set editable=True
in GenericRelation subclass.

Thanks to Trac alias joshcartme for the report and stephencmd and Loic
for working on this issue.

Backpatch of 0e079e4331a8be4dbd18d5e5776116330b0a5e61 from master.
[1.6.x] Fixed a regression caused by fix for #21428

On Python 3 sorting Fields mixed with GenericForeignKeys doesn't work
as GenericForeignKey isn't a subclass of django.db.models.fields.Field.

Refs #21428.

Backport of 326539f6a4 from master
Updated humanize translations and added release note.

Refs #21415.
[1.6.x] Fixed #21404 -- Added session.set_expiry() note to 1.6 release notes.

Thanks pwr for the suggestion.

Backport of ffdae5b66d from master
[1.6.x] Fixed #21240 -- Added 1.5 release note for OneToOneField/select_related change.

Thanks marcin at sokrates.pl.

Backport of ba63b9895b from master
[1.6.x] Fixed #20852 - Fixed incorrectly generated left quotes in docs.

Sphinx generates left single quotes for apostrophes after
code markup, when right single quotes are required. The
easiest way to fix this is just by inserting the unicode
character for a right single quote.

Instances of the problem were found by looking for
">&#8216;" in the generated HTML.

Backport of c33d1ca1d98003de29cdecb6080b52c5c52139bd from master.
[1.6.x] Added release note for TypedChoiceField coerce limitation

Thanks Elec for the report and Simon Charette for the review.
Refs #21397.
Backport of 4a00f132e0 from master.