This post contains some mild spoilers about the plot of The Irishman. Martin Scorsese's The Irishman is a towering, winding journey into the past. Not just the general past, mind you, but one man's past — Frank Sheeran (Robert De Niro) — as he becomes ingratiated with the Bufalino crime family through Russell Bufalino (Joe Pesci) and grows close to labor union leader Jimmy Hoffa (Al Pacino). Just knowing Pacino is playing Hoffa means there's a good chance you know The Irishman is going to have to address the unsolved case of Hoffa's disappearance in 1975 (he was …