[NFC][relnotes] Advertise RooFit RDF helpers also in RDF relnotes
[NFC][relnotes] Advertise RooFit RDF helpers also in RDF relnotes

olifre/root,olifre/root,olifre/root,olifre/root,olifre/root,olifre/root,olifre/root,olifre/root,olifre/root,olifre/root,olifre/root