Add ar-001, rhg-arab and rhg-rohg

[jdforrester]

Wikifunctions carries these three codes as languages users can write labels in, and WikiLambda reads label directionality from ULS via $.uls.data.getDir(). ULS answers 'ltr' for any code it does not know, with no error and no fallback to the base subtag, so all three currently render left-to-right when they should render right-to-left.

ar-001 is CLDR's code for Modern Standard Arabic and rhg-rohg is the Hanifi-script Rohingya that the bare rhg code already denotes, so both are redirects. rhg-arab needs an entry of its own; its autonym is taken from the corresponding Wikifunctions object.

Twenty-one further right-to-left codes that Wikifunctions carries are still missing, and seven of them use scripts absent from rtlscripts (Avst, Mand, Orkh, Phli, Phnx, Samr and Sogd). Those are not included here because none of them has an autonym available from a source that has already been reviewed, and guessing at native-language names for extinct languages seemed worse than leaving them out.

Assisted-by: Claude Opus 5

[jdforrester]

Thanks! Is there a standard place from which to get the autonyms for the other languages?

[srish]

@jdforrester Sources provided by communities are relied on for autonym evidence. Ethnologue is also a go to resource among many others documented at https://www.mediawiki.org/wiki/Manual:Adding_and_removing_languages#Determining_the_autonym.