THE MOST EVOCATIVE WORD with which to describe Kelly Reichardt’s films is “homespun,” in the sense of something that is handmade and textured, the opposite of slick, glossy, or eye-catching. Reichardt is a prolific filmmaker, at least among those who make small independent features. Until now, her most fully realized and deeply affecting works were Wendy and Lucy (2008) and the third section of Certain Women (2016), a two-hander for Kristen Stewart and the remarkable Lily Gladstone in her first substantial role. Wendy and Lucy stars Michelle Williams, as does Reichardt’s latest film, Showing Up