Windows: Wrong file location path comments in .po files generated by makemessages

[Ramiro Morales]

The comments associated with literals found on files of the 'django' domain that aren't Python source code end like this (from the test suite):

# .\template\test.html.py:55
msgid "The translatable literal here"

it should be:

# template\test.html:55
msgid "The translatable literal here"

to be on par with the file generated on Unix, or even possibly:

# .\template\test.html:55
msgid "The translatable literal here"

But the .py prefix shouldn't be leaked.

[Ramiro Morales <ramiro@…>]

In 4b715fc05a75c375d5afe1860ce748ae2a2e290b:

Fixed #21209 -- .po file path comments on Windows.

Literals from source files with Django template language syntax don't
have a '.py' suffix anymore.

Also, the '.\' prefix is preserved to respect GNU gettext behavior on
that platform.

Refs #16903.

[Ramiro Morales <ramiro@…>]

In d16753eecd3c97c781382fbb4c119f6bae314487:

[1.6.x] Fixed #21209 -- .po file path comments on Windows.

Literals from source files with Django template language syntax don't
have a '.py' suffix anymore.

Also, the '.\' prefix is preserved to respect GNU gettext behavior on
that platform.

Refs #16903.

4b715fc05a from master.