Fixed #22056 -- Omitted non-package directories when collecting tests

This allows us to ignore empty dirs or other unrelated dirs.
Thanks Sebastian Pawluś for the report and the initial patch.
Fixed documention typo
Merge pull request #2374 from spaceexperiment/doc_typo

Fixed documention typo
Fixed #22136 -- Updated comment for Textarea widget

Thanks Aymeric Augustin for the suggestion.
Replaced deprecated assertEquals
Fixed #21962 -- Added escape_html flag to ErrorDict.as_json()
Removed Django 1.5 upgrade hints for {% url %} tag.

Refs #19280 and Refs #19392.
Fixed #22129 -- Added steps for creating superusers to tutorial.
Fixed #22028 -- Documented that database signals aren't emitted for apps that laack a models module.

Thanks un33k for the suggestion and donjpacheco for the draft patch.
Fixed doc typos.
Fix keyword agument names in RunPython to be positional
Fixed #21948 -- Noted TEMPLATE_LOADERS requirement when overriding admin templates.

Thanks django at patjack.co.uk for the suggestion.
Removed some ReST links to undocumented functions.
Added release note and regression test for refs #21643.

This will be backported to stable/1.6.x along with the original fix.
Fixed spelling mistakes in docs.
Added patch_formats utility for i18n formatting tests
Fixed #22137 -- Made Widget.is_hidden a read-only property

Thanks django at patjack.co.uk for the report and the review.
Fixed #22168 -- Fixed migrations failing on sqlite when column names are SQL keywords

Thanks to trac user fallen_flint for the report and initial patch.
Fixed #15318 -- Added settings for language cookie max-age, path, domain

Introduced a number of settings to configure max-age, path, and domain
for the language cookie: LANGUAGE_COOKIE_AGE, LANGUAGE_COOKIE_PATH and
LANGUAGE_COOKIE_DOMAIN.

Thanks sahid for the suggestion.
Fixed #22130 -- Deprecated fix_ampersands, removed utils.clean_html()