Questioned by The Hollywood Reporter about whether she’d be interested in a third Sex and the City movie, Cynthia Nixon had the air of a mother stripping a kid of an inane toy she’s been fiddling with for far too long: “No, no. I think we had a wonderful ride. I think it’s fine to let it go.†Nice — tactful, strong, and totally not what Sarah Jessica Parker has said about a threequel.