Thanks Tom Christie for review.

This fixes django-taggit and reflects some places where duck-typing may not
be appropriate.

This reduces the possibility of a naming conflict, especially after
squashing migrations.

Thanks Tim for the review and pointing out this was fixed by #26207.

Refs #26572, #17281. The RFC doesn't limit total length, just the line length
which is already taken care of by Python itself.
Thanks Tim Graham for the review.

Didn't rename django.utils.feedgenerator.rfc2822_date()
as some external code may rely on it.

Refs #26536.

Thanks Sylvain Fankhauser for the very detailed report.

Calling conditional_escape() on SafeData won't change it.

Thanks to Andriy Sokolovskiy for initial patch.

Useful for overriding the DateTimeField widget.

The WGS84 proj string can differ depending on installed libs.
Refs #26592.

Thanks Michael Bitzi for the reporti and Tim Graham for the review.

On Python 3, sending emails failed for addresses containing non-ASCII
characters due to the usage of the legacy Python email.utils.formataddr()
function. This is fixed by using the proper Address object on Python 3.

The docs say that these headers always appear without the HTTP_ prefix.
This may have been an oversight when they were added in
d725cc97, the only commit that uses
these names.

Thanks Tim Graham for the review.

Thanks Tim Graham for completing the initial patch.