Avoid unnecessary translation work by removing language name from translations

[teolemon]

What

Language name can be probably translated using https://perldoc.perl.org/Locale/Language.html

Part of

• 🌐 Improve the translator journey (tracker) #5528

[hangy]

That Perl module seems to be insufficient, because it only supports English. We might be able to use Locales though, as it's built on Unicode CLDR and should be more complete.

[teolemon]

I believe we fixed that by using the Languages taxonomy.