In the race for attention from booze marketers, Twitter has lagged Facebook, which has inked high-profile ad deals with the likes of Heineken and Diageo. But Twitter is making up ground, thanks in part to an age-checking tool being tested by big brands such as Coors Light. Twitter is making the changes in response to lobbying from the alcohol industry, whose revised marketing code requires brands to check ages before engaging fans on social media. At the same time, beer, wine and spirits marketers could soon face more scrutiny from the Federal Trade Commission, which is seeking digital-marketing data from alcohol advertisers for its next major study on booze marketing. Age-gating has been smoother on Facebook because…