Sometimes, the rain stops and the sun shines over the River Clyde—or at least it does in these two classic coming-of-age comedies by the treasured Scottish filmmaker Bill Forsyth. Delighting in the boyish charms of their nonprofessional actors, That Sinking Feeling (1979) and Gregory’s Girl (1980) follow groups of scruffy, shaggy-haired lads with big dreams. Precocious...