scripts: fix translations
This PR fixes two localization issues.
Some locale keys were incorrectly processed
Translations with a comma in the key are rewritten to be on a single
line. But this failed when the comma was just preceded by a dot (like in
etc.,). Consequently, some strings were not correctly localized.
This PR fixes the locales preprocessing script, so that it works with all locale keys.
Invalid locale key
A locale key was incorrectly specified, and thus trigerred an "missing key" error.