NONFICTION While major golf championships end on spring and summer Sundays, for thousands of fans these tournaments aren’t really over until they have been sliced and diced by Dan Jenkins in the next edition of Golf Digest. Jenkins, a 79-year-old Texan, is a successful novelist (“Semi-Tough,“ “Dead Solid Perfect”), but he’s at his best as a journalist. He has been covering golf for newspapers and magazines for six decades, and by his count he has been a member of the working press at 198 major championships. He’s currently covering his 199th, the U.S. Open that concludes today in Farmingdale, N.Y.