Be more flexible when deciding if we should render RTL
Currently we only render RTL if the language exactly matches one of: 'ar', 'he', 'fa', 'gu_IN', 'ku'.
We should prefer to render RTL for the language, no matter which country/region is specified. Splitting on the '_' and making out decision based on the first two characters should suffice, i think (or simply always comparing [:2] may work just as well.