wrap long words in field labels on admin forms, closes #18755

Otherwise, words overlap into the fields themselves, which makes the labels
unreadable.
Fixed #19690 - Removed unused import
Removed an import of a class unused in the Ajax example.
fixed minor typo #19703
Fixed #19160 -- Made lazy plural translations usable.

Many thanks to Alexey Boriskin, Claude Paroz and Julien Phalip.
Fixed #19076 -- Added content_type attribute to TemplateView.

Thanks Gavin Wahl.
Changed "versionadded" after the decision to backport.

Refs #19076.
Fixed #19034 -- Added proper i18n pluralization for max/min length validation messages

This was made possible by commit 3f1a0c0040b9. Thanks Evil Clay
for the report and Alexey Boriskin his work on the ticket.
Added file forgotten in 23e319d7.
Merge pull request #686 from skrr/ticket_19703

Fixed #19703 -- Typo in get_declared_fields docstring
Attempted to reduce version mismatch problems in the tutorial.
Fixed #19692 -- Completed deprecation of mimetype in favor of content_type.

Thanks Tim for the report and initial patch.
Fixed #19708 -- Exception in timezone.override(None).

Thanks rafales.
Deprecated undocumented warnings manipulation testing tools.
Fixed #19711 -- Typo in __all__ declaration in django/test/simple.py
Merge pull request #690 from rafales/ticket_19711

Fixed #19711 -- Typo in django.test.simple.__all__
Added introspection tests for most of Django model fields
Fixed #19709 -- Fixed TimeField introspection on MySQL

Thanks Eugene Grachev for the report.
Fixed #19341 -- Detected NullBooleanField when introspecting models

Thanks Tim Bowden for the report.
Fixed dict randomization issue in inspectdb
Renamed inspectdb field names for clarity