Fixed #21341 -- Eased https requests with the test client

All request methods of ``django.test.client.Client`` receive a ``secure``
argument that defaults to ``False`` indicating whether or not to make the
request through https.
Thanks Aymeric Augustin for the review.
Fixed #21373 -- Typo fixed in i18n docs

Thanks rpq at winscores.com for the report.
Fixed #21366 -- regression in join promotion logic

The regression was caused by ecaba3602837d1e02fe1e961f7d3bf9086453259
and affected OR connected filters.
Django should be capitalized in text
Merge pull request #1847 from Bouke/docs/django

Django should be capitalized in text
Fixed #21375 -- related_name='+' clashed with other '+' names
Fixed #21302 -- Fixed unused imports and import *.
Correct flake8 violation E261
Merge pull request #1848 from rayashmanjr/master

Correct flake8 violation E261
Fixed flake8 E241
Replaced a hardcoded "2" with the right named constant
Merge pull request #1849 from brabadu/master

Fixed flake8 E241
More attacking E302 violators
Fixed #14511 -- bug in .exclude() query
Fixed syntax error in queries/tests.py
Fixed all E261 warnings
Correct flake8 E302 violations
Fixed failing test around DST change.

The timezone arithmetic done in JS can be off by one hour around DST
change. We work around this issue by adding one extra hour to the test
error margin when we detect a DST change is near.

Refs #20663.
Revert change to django/test/_doctest.py
Checkout prior commit of _doctest.py