Ref T5267. Ref T4103. Currently, adding new locale support to the upstream fills this menu with confusing options which don't do anything. Separate it into four groups:
- Translations: these have a "reasonable number" of strings and you'll probably see some obvious effect if you switch to the translation.
- Limited Translations: these have very few or no strings, and include locales which we've added but don't ship translations for.
- Silly Translations: Pirate english, etc.
- Test Translations: ALLCAPS, raw strings, etc.
Czech is currently in "test" instead of "limited" for historical reasons; I'll remedy this in the next change.
