checking for "Skolemized" blank nodes in Wikidata results

[pfps]

Because of limitations in Blazegraph :-(, the Wikidata dumps have "Skolemized" blank nodes instead of real blank nodes. So checking for a blank node is supposed to be done by wikibase:isSomeValue.

@hannah Does this need to be added to QLever, or is there some good way of doing this?

I have for now patched language-index with (! (STRSTARTS(STR(?language),"_")))