Is your feature request related to a problem or area of OpenRefine? Please describe.
It could be nice to add a JSON-LD importer, for semantic data stored in that format. In OR v3, you can import JSON-LD data with the JSON importer, but it wont be parsed as semantic data, whereas XML/RDF data is parsed as semantic data, and not imported as ordinary XML.

Describe the solution you'd like
With the same "semantic" dataset expressed in different format (RDF/XML, N3, Turtle, JSON-LD...) we should get the same result in Openrefine.
From UX point of view, maybe we could rename the importer menu "Semantic data" with options : "Semantic data (RDF/XML)", "Semantic data (JSON-LD)", etc., to make it clear that it is not ordinary JSON and XML data?

Describe alternatives you've considered
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Additional context
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