Fixed #23298 -- Made makemessages actually ignore specified dirs on Windows.

This was detected by two failures in the i18n.test_extraction of our
test suite.

Refs #20422, refs #22336
Fixed #23263 -- Added sqlmigrate to migration topic guide.
Fixed #23309 -- Fixed call_command to parse args correctly
Merge pull request #3075 from ramiro/makemessages-ignore-windows

Fixed #23298 -- Made makemessages actually ignore specified dirs on Wind...
Fixed #14638 -- Clarified model Field.to_python() docs.

Thanks Anubhav Joshi for the patch.
Fixed #23303 -- Added BEGIN and COMMIT statements to the output of sqlmigrate.
Fixed #23136 -- Added a message when sqlclear does nothing
Fixed flake8 warning.
Removed test, duplicate of admin_scripts.CommandTypes tests
Fixed #22171 -- Improved sanitize_separators cleverness

Thanks Klaas van Schelven for the report and Tim Graham for the
review.