Gamesettings were split from GUI game setup in r25077, but binaries/data/mods/public/l10n/messages.json was not updated to match the new path of gamesettings.
As a result, translation message extraction hasn't picked up messages from files in binaries/data/mods/public/gamesettings/attributes.
Updates messages.json to store messages extracted from the correct path for gamesettings in a new output file, public-gamesettings.pot.