Onwards and Sideways stars Laura Linney and Rhys Ifans as two people with a lot in common – a great sense of humor, a love of dance, and, as just diagnosed, Parkinson’s. The movie, directed by John Madden (Shakespeare in Love, Operation Mincemeat, The Best Exotic Marigold Hotel), based on a script by Paul Mayhew-Archer (The Vicar of Dibley, Roald Dahl’s Esio Trot and co-host of Parkinson’s podcast Movers and Shakers), will world-premiere in a gala screening at the Toronto International Film Festival (TIFF) on Sunday, Sept. 13. The film stars Emmy and Golden Globe winner Linney (Ozark, Love Actually, John Adams) opposite BAFTA winner…