Show language codes in addition to translated language names in switch application language dialog.

While adding the KDE standard "Switch Application Language" menu entry to the help menu in RKWard, I stumbled across the fact that this shows translated language names, rather than native Language names. E.g. while in English locale, German is shown as German, rather than "Deutsch". This become particularly troublesome, if you have (accidentally) selected a language that you are not familiar with at all. Good luck figuring out, what your native language is called in Ukrainian, for instance.

This patch adds the language code in order to assist in that case, and add clarity among language variants at the same time.