Fixed #19690 - Removed unused import in doc examples

Thanks Jonathan Liuti for the report and the initial patch, and
Simon Charette for the review.

Thanks James Pic for the suggestion (PR 88).

Thanks Chris Rebert for the report.

Fixed #18755 -- Wrapped long admin forms fields labels.

Refs #16218.

Thanks Aramgutang for the report. Refs #17228.

Thanks Tim Bowden for the report.

Thanks Eugene Grachev for the report.

Fixed #19711 -- Typo in django.test.simple.__all__

Thanks rafales.

Thanks Tim for the report and initial patch.

Fixed #19703 -- Typo in get_declared_fields docstring

This was made possible by commit 3f1a0c00. Thanks Evil Clay
for the report and Alexey Boriskin his work on the ticket.

Refs #19076.

Thanks Gavin Wahl.

Many thanks to Alexey Boriskin, Claude Paroz and Julien Phalip.

They are simply ignored now. This allows for a more correct behavior when
they are placed before translatable constructs on the same line.

Previously, the latter were wrongly ignored because the former were
preserved when converting template code to the internal Python-syntax
form later fed to xgettext but Python has no ``/* ... */``-style
comments.

Also, special comments directed to translators are now only taken in
account when they are located at the end of a line. e.g.::

  {# Translators: ignored #}{% trans "Literal A" %}{# Translators: valid, associated with "Literal B" below #}
  {% trans "Literal B" %}

Behavior of ``{% comment %}...{% endcomment %}``tags remains unchanged.

Thanks juneih at redpill-linpro dot com for the report and Claude for
his work on the issue.

Previously, some properties weren't set unless
confirm_spatial_components_versions() was explicitely called.

Removed an import of a class unused in the Ajax example.

Thanks sunsongxp@ for the report.

Refs #16630.

Refs #16630.

Thanks Georgy Kutsurua for the report and Simon Charette for the patch.

Thanks Simon Charette.