Fixed #20733 -- Typo in docs/ref/class-based-views/generic-display.txt

Thanks ijl20@ for the report.
Fixed #13721 -- Added UploadedFile.content_type_extra.

Thanks Waldemar Kornewald and mvschaik for work on the patch.
Fixed #20730 -- Fixed "Programmatically creating permissions" error.

Thanks glarrain for the report.
Fixed #17471 -- Added smtplib.SMTP_SSL connection option for SMTP backend

Thanks dj.facebook at gmail.com for the report and initial patch
and Areski Belaid and senko for improvements.
Fixed #20735 -- clarified ManyToManyField constructor doc
Merge pull request #1350 from chrismedrela/ticket20735

Fixed #20735 -- clarified ManyToManyField constructor doc
Fixed #17528 -- Documented that add() and remove() with a many-to-many relationship do not call Model.save()
Added clarification comments to django.utils.image; refs #19934
Merge pull request #1349 from chrismedrela/ticket19934-comment

Added clarification comments to django.utils.image; refs #19934
Fixed #19031 -- Added a warning when using override_settings with 'DATABASES'
Fixed #20429 -- Added QuerySet.update_or_create

Thanks tunixman for the suggestion and Loic Bistuer for the review.
Fixed #20625 -- Chainable Manager/QuerySet methods.

Thanks akaariai for the initial patch and charettes, mjtamlyn and timgraham
for the reviews.