[jena] Adding JSON-LD Writer instance

Tested with:
    val r = jsonldCompactedWriter.write( graph, os, endpoint )

Comments and code syntax enhancements:

Added some documentation for Generic Parameters, not with @tparam but by a reference in the text.
	NOTE: other @tparam remain elsewhere.
Fix typo in class definition of Transactor regarding typeclass name A .
in JenaModule and JenaRDFWriter, remove useless package path org.w3.banana.io ; add a space after the commas.

Updaded the pre-commit message.
[jena] Adding JSON-LD Writer instances: No more three typeclass instances all plugged to the same implementation : the only Jena implementation has been associated to Compacted Document Form http://www.w3.org/TR/json-ld/#compacted-document-form