It’s a striking image — a young Black man, dressed in 18th-century French fashion, in a waistcoat and silk breeches, his hair braided in cornrows, holding a violin, the bow slung over his shoulder, the title “Chevalier” emblazoned below his feet. This movie poster almost looks like a Kehinde Wiley portrait, a radical reassertion of tradition, a disruption of the narrative we’ve been sold. This is a story that’s been crushed under the brutal wheel of history, war and racism, and the film “Chevalier,” about the composer and violinist Joseph Bologne, Chevalier de Saint-Georges, promises to unfurl this lost story in modern, exciting fashion.