Lame horses get shot and broken cowboys get put out to pasture in Chloé Zhao’s The Rider, a soulful, touching look at ranchers and riders in the modern American heartland, based on the real-life experiences of its lead, former rodeo performer Brady Jandreau. Zhao, who previously looked at vulnerabilities on the open plain in 2015’s Songs My Brother Taught Me, casts unknowns and keeps the film light and loose, its wide open landscapes of sky and rock the backdrop to the pain of a talented rodeo cowboy forced to hang up his stirrups and face the existentialist wilderness after suffering a…