Gilly (Hannah Murray) continues: "Maynard says here that he issued an annulment for a Prince 'Raggar' and remarried him to someone else at the same time in a secret ceremony in Dorne."
The Prince she's referring to seems to be Rhaegar Targaryen, whom we found out last season had a baby with Ned Stark's sister Lyanna. This could mean that Rhaegar and Lyanna were actually married in secret, and therefore Jon Snow wouldn't have been a bastard.
