True love endures, but cannot obscure injustice, in director Barry Jenkins’ big-hearted if slightly patience-testing follow-up to his Oscar winner “Moonlight.” An adaptation of a James Baldwin novel, “If Beale Street Could Talk” follows a young couple — Tish (KiKi Layne) and Alonzo, nicknamed Fonny (Stephan James) — in 1970s Harlem, struggling against omnipresent racism...