A Delaware Court of Chancery judge has rejected a motion from activist investor HoldCo Asset Management that sought to legally block Fifth Third's acquisition of Comerica.On Jan. 14 -- the day after the deal had received all necessary regulatory approvals and a Feb. 1 closing date was set -- HoldCo filed an emergency motion for temporary restraining order to stall the merger's closing. Vice Chancellor Morgan T. Zurn denied HoldCo's motion Friday."Enjoining a premium merger on the eve of closing will introduce substantial delay and uncertainty," Zurn wrote in a Monday filing explaining her denial. "While HoldCo mourns a topping...