Walt would like to read you a story. It’s a story he wrote about himself, and the empire he made, and the city of the future he’s building that will change everything. It’s about his brother, and it’s about everyone, and how they all love him, and how they’ll all miss him so much when he’s gone. ...Right? Lucas Hnath’s A Public Reading is a darkly comic inversion of the Walt Disney persona, a funny and moving meditation on fame,…