By Ron Charles, Washington Post Writer’s Group We love Ann Patchett for her novels, but her new one, “Commonwealth,” reminds us that, in another world, she could have been one of our favorite short story writers, too. When she edited “The Best American Short Stories” in 2006, she singled out Eudora Welty as “the hero of my life,” and that veneration shows in the adroitly shaped, exquisitely subtle scenes that make up her fiction. “Commonwealth” opens with a 32-page story about a party at Fix Keating’s house in Los Angeles.