When you hear about filmmakers in conflict zones, you may flash on countries like Syria or Afghanistan. The movies produced in theaters of war often follow a similar arc: The documentarian parachutes in to take stock of a catastrophe. The focus tends to be on rubble, blood and suffering — the spectacle. In her short, stellar career, the Chinese filmmaker Nanfu Wang has repeatedly returned to a less obvious conflict zone in which the war for proverbial hearts and minds mostly takes place through state propaganda. Her latest, “In the…