The actor Henry Winkler spent 11 seasons playing The Fonz on “Happy Days,” and for much of that time, he was struggling with an undiagnosed learning disability. He only realized he had dyslexia at age 31, when his stepson was diagnosed. Now, Henry is a prolific children’s author who’s helping kids who have trouble with literacy. He joins Tom Power to talk about the latest book in his “Detective Duck” series, the shame he felt as an actor who struggled with reading, and what happens when you admit you need help.