Rolling Stones guitar guru Keith Richards met his sartorial match when he appeared backstage at the Broadway show “Kinky Boots.” We hear that the rock god was recently introduced to the stars of the flamboyant musical, Stark Sands and Billy Porter — and that Porter, in full drag, tried to goad Richards into trying on a pair of the show’s titular thigh-highs. Richards demurred. But he was seen grooving in the aisles to the “Kinky” curtain-call finale, with music by Cyndi Lauper.