The nation's two top-selling men's magazines didn't do too badly anticipating events in spite of their three- month lead times: the current Playboy features a harsh look at Alexander Haig, and Penthouse got lucky with a cover story whose headline reads "Plead Insanity and Get Away With Murder" . . . William Morrow & Co. this month publishes a new novel, The Second Saladin, by Baltimore Sun movie critic Stephen Hunter .. . Time writer Ned Scharff (late of The Washington Star) is on leave to write a book about The Wall Street Journal, and he has the cooperation of the newspaper .. . Home grown actress 815 Donna Dixon lands a role in a new Dan Aykroyd movie about to begin filming in Chicago called "Dr. Detroit." It's a comedy and Dixon plays the part of a high-priced call girl ...Tom Korologos, vice president of the Washington lobbying firm Timmons & Co., is writing a book for Addison-Wesley that grew out of a Washingtonian piece about the jargon peculiar to this town. Called WashingtonSpeak, the book will translate such abbreviations as OMBies Zombies (an Office of Management and Budget employee) and explain the real meaning of: "Let's have lunch sometime" and "I'll give you a call" and "Let's get together real soon." All of which, says Korologos, are "official kiss-offs."