Filter datasets by language code
Hi! I use the language search field on https://huggingface.co/datasets
However, some of the datasets tagged by ISO language code are not accessible by this search form.
For example, [myv_ru_2022](https://huggingface.co/datasets/slone/myv_ru_2022) is has `myv` language tag but it is not included in Languages search form.
I've also noticed the same problem with `mhr` (see https://huggingface.co/datasets/AigizK/mari-russian-parallel-corpora)
The dataset still can be found, if instead of using the search form you just enter the language code in the url, like https://huggingface.co/datasets?language=language:myv. 

But of course having a more complete list of languages in the search form (or just a fallback to the language codes, if they are missing from the code=>language mapping) would be much more convenient! Hi! I've opened a PR to make these languages searchable on the Hub. Thanks @mariosasko!
Do you think it is possible to turn this into a more scalable pipeline? Such as:
1. Looping through all the datasets on the hub and collecting the set of all their language codes;
2. Selecting the codes not covered yet in `Language.ts`
3. Looking up their codes at https://iso639-3.sil.org/code_tables/639/data
4. Adding all the newly found language codes to `Language.ts` @avidale This has been discussed in https://github.com/huggingface/datasets/issues/4881, so also feel free to share your opinion there.