After backlash from customers, the producer of Maker’s Mark bourbon is reversing a decision to cut the amount of alcohol in bottles of its famous whiskey. Rob Samuels, Maker’s Mark’s chief operating officer, said Sunday that it is restoring the alcohol volume of its product to its historic level of 45 percent, or 90 proof. Last week, it said it was lowering the amount to 42 percent, or 84 proof, because of a supply shortage. “We’ve been tremendously humbled over the last week or so,” Samuels, grandson of the brand’s founder, said of customers’ reactions. The brand known for its...