Weblate doesn't show the "other"/"others" categories as translatable strings

[MarcAbonce]

Version of SearXNG, commit number if you are using on master branch and stipulate if you forked SearXNG
61853aa (current master)

What happened?

Weblate doesn't show the "other"/"others" categories as translatable strings. They do not show up in any of the messages.po files either, even though all the other new subcategories already appear in there.

How To Reproduce

1. Go to Weblate.
2. Try to find the "other" string.

Expected behavior

1. Strings should be translatable.

Additional context

I think that the script used to generate the messages.po files wasn't able to pick up those strings because they are defined outside the gettext, see: https://github.com/searxng/searxng/blob/master/searx/webapp.py#L189-L190

...
    gettext('web'),
    gettext(DEFAULT_GROUP_NAME),
    gettext(OTHER_CATEGORY)
)

[not-my-profile]

Ah yeah my bad ... I thought that the gettext functions actually did something, I guess the strings are extracted statically.

[return42]

May be we can use https://babel.pocoo.org/en/latest/messages.html#writing-extraction-methods

I got this tip from python-babel/babel#807 (comment)

[return42]

I think that the script used to generate the messages.po files wasn't able to pick up those strings because they are defined outside the gettext

@MarcAbonce I fixed this issue in PR #859 .. if you have time for, would like to have a look at this PR? / thanks!