ⓒCourtesy of Bleecker Street Just prior to its debut today in Venice, a preview clip had been released for a new Elon Musk-focused documentary feature, “Musk” from Oscar-winning filmmaker Alex Gibney, best known for “Going Clear,” “Taxi to the Dark Side,” and “Enron: The Smartest Guys in Room.” “Musk” is a nearly four-hour film (232…