TCM’s salute to musicals continues – and tonight, in prime time, it begins with Swing Time, the 1936 stylish musical – music by Jerome Kern, lyrics by Dorothy Fields – that shows Fred Astaire and Ginger Rogers in fine form indeed. And at 10 ET, the salute continues with 1933’s 42nd Street, the early Busby Berkeley musical that helped make a star of, among others, Ruby Keeler.