A wise man once told me that “humor conceals a deep sadness.” In that spirit, “The Ballad of Wallis Island” is a gentle comedy about profound loss. The movie has many virtues: two multilayered lead performances, three fine supporting turns, excellent original songs, and gorgeous scenery. If you’d like to feel a little better about humanity, you should seek out this film at the Savoy Theater. “The Ballad of Wallis Island” centers on two demoralized men: Charles (Tim Key), a widow...