Write logic to test for CLDR alphabet being found and turn it into a whitespace-separated string.
Mockup
Open questions
- Which UI works best?
Implementation
- Get AlphabetsProvider from the service registry MediaWikiServices::getInstance()->getService( 'Cite.AlphabetsProvider' )
- Use AlphabetsProvider::getIndexCharacters to get the Alphabet from CLDR
- Use the content language as parameter
- We then would probably want to forward that to the config page as JS


