(Corrects “automatic” to “semi-automatic” in 6th paragraph) By David Morgan and Moira Warburton WASHINGTON (Reuters) -The U.S. Senate took an initial step toward passing the country’s first major gun-control legislation in decades on Tuesday, galvanized by two mass shootings in a nation that has long struggled to curb chronic gun violence. Senators voted to speed passage of a bipartisan package of measures to toughen federal gun laws. The Senate is expected to vote on the 80-page bill this week before a two-week recess. The bill unveiled on Tuesday does not go as far as Democrats, including Pr…