Bungling MSNBC bigwigs accidentally printed out details about the left-leaning network’s impending jobs bloodbath — and the top-secret document was found by a stunned staffer who leaked the details to co-workers, The Post has learned. The production assistant stumbled across the “kill list” at MSNBC’s 30 Rock headquarters in midtown Manhattan shortly before the cuts were announced on Monday, Feb 24, sources close to the situation said. The printed pages, which were viewed by The Post, laid out meetings to be held with workers and “talent” about their fate in ominously-dubbed “impact conversations,” the insiders said. “On the Monday, management...