(previews start on Wednesday; opens on April 20) Ren�e Fleming and her luscious, lyric soprano will make their Broadway debuts in Joe DiPietro's update of Garson Kanin's "Peccadillo." Under Kathleen Marshall's direction, Ms. Fleming plays an opera diva (not exactly a stretch) who is writing her autobiography. But her husband (Douglas Sills) is writing one, too.