From William Shakespeare to Oscar Wilde to Noel Coward, British playwrights have always been known for lightening up their dark comedies with biting wit. That includes the current crop of writers such as Nina Raine, whose “Tribes,” which played Steppenwolf Theatre last year, took a painful, yet often-humorous look at the family life of a deaf young man.That theme is not unlike that found in the one-act “The Herd” by the established actor and first-time English playwright Rory Kinnear, currently at …