A restaurant in Chicago’s River West filed suit against its insurance company on Tuesday, seeking a Cook County judge’s declaration that its business-interruption policy must cover losses suffered during the governor’s shutdown of dine-in restaurant services.That policy, according to the owners of the Maillard Tavern at 494 N. Milwaukee Ave., is written to cover losses from a “necessary suspension” of operations during a “period of restoration.” The policy language says it will pay …