Registries for triple/quad RDF languages and result set languages

### Version

4.6.1

### Feature

From mailing list: https://www.mail-archive.com/users@jena.apache.org/msg19661.html

Suggested new methods: `RDFParserRegistry::registeredLangTriples`, `RDFParserRegistry::registeredLangQuads`, `ResultSetReaderRegistry::registered`.

### Are you interested in contributing a solution yourself?

Yes