John Green’s first novel in nearly a decade is also a kind of debut — a work of fiction for adults. The author of such favorites for young people as “The Fault in Our Stars” and “Looking for Alaska” has written a story about celebrity and the attention economy, “Hollywood, Ending.” Dutton Books, a Penguin Random House imprint, will release the novel on Sept. 22. According to Dutton, “Hollywood, Ending” centers on two young actors and how their lives change through their roles in the biopic “