Tagging Wikidata Query UI since [AUTO_LANGUAGE] is handled there (we just replace the string before sending the query to the backend).

I suppose this would be easier to implement now than it was back in 2017 when [AUTO_LANGUAGE] was introduced, because the languageinfo API exists now and can tell us the list of fallback languages. But fetching the fallbacks would still require an async API call. Not sure if we want to do that

1. when the user first runs a query (and then cache it as long as the page stays open – or even in local storage for a while?)
2. when the user first opens the query GUI (on the assumption that it’ll probably be needed; and then cache it as above)
3. when we build the query GUI, and then the fallback chains are hard-coded in the build output?

(Also, I feel like we should probably make this a separate keyword, perhaps [AUTO_LANGUAGES], to avoid breaking queries that rely on [AUTO_LANGUAGE] returning a single language code – anything with FILTER(LANG(?itemLabel) = "[AUTO_LANGUAGE]"), for example.)

Tagging the Product Platform on this after a quick discussion w. Leszek