Update dialog: Fix incorrect version info when using some translations.

Belarusian, Slovenian and Russian translations were affected after 607c1f53de95e572ff63b4e293b31650d92892df.

This commit fixes #4020.
Update translations from Transifex:

 - Czech
 - Galician
 - Swedish
Language menu: Ensure "Language" always appears in English in menu entry.

If "Language" doesn't appear in the translated string, "(Language)" will be appended automatically.
Language menu: Use submenus to group language names starting with the same character.
Update translations from Transifex:

 - Greek.