Fixed flake8 warning.
Made a doctest compatible with Python 2

That test might not always execute, but can be executed when the
parent test label is explicitely given.
Fixed versionchanged indentation in unit-tests.txt.
Fixed #23630 -- Made AlterModelTable rename auto-created M2M tables.

Thanks Naddiseo for the report, Andrew Godwin for guidance,
and Shai Berger for review.
Fixed #23705 -- Removed unnecessary AliasMatch from example Apache config.

Thanks Keryn Knight for the report.
Added missing available app in migrations test case

In some test combinations, having contrib.auth available but not
contrib.contenttypes can produce failures while creating permissions.
Fixed #23444 -- Deprecated django.contrib.admin.helpers.InlineAdminForm.original_content_type_id
Fixed #23702 -- Fixed adding an explicit id field on SQLite.

Thanks gavinwahl for the report.
Fixed #23707 -- Prevented discovery of duplicated tests