Gwen Stefani took to social media to share that she and her husband, Blake Shelton, were celebrating an absolutely incredible career milestone.MORE: Gwen Stefani makes surprise health confession in emotive speech to her fansThe pop star shared pictures of two matching jars of chocolates for her and her hubby on her Instagram Stories celebrating The Voice.She also posted a note from the showrunners that revealed that the jars of 500 chocolates were sent over to mark 500 episodes of the