While Kanye West was playing court jester in the Oval Office last Thursday, bragging about having an IQ in the 98th percentile and revealing that wearing a Make America Great Again cap made him “feel like Superman,” Sylvie Simmons, author of “I’m Your Man: The Life of Leonard Cohen,” was discussing her favorite subject’s recent act: trolling the Trump-loving rapper from beyond the grave. Cohen, the deep-voiced troubadour who wrote some of rock’s most widely admired lyrics —“S