Generally speaking, the world’s top golfers don’t reveal much about their feelings. Tiger Woods and Ben Hogan might as well have tattooed “keep out” on their foreheads. Even more affable golfers such as Jack Nicklaus and Tom Watson seldom let their emotions slip. Rory McIlroy, by contrast, has always played and discussed his performance with heartfelt feeling. That maybe hasn’t been the best strategy for staying focused under pressure, but it has endeared him to fans and provided Alan Shipnuck with lots of material to work with in “Rory: The Heartache and Triumph of Golf’s Most Human Superstar.” Mr. Shipnuck…