By Nate Raymond BOSTON (Reuters) – A U.S. appeals court on Monday revived a $10 billion lawsuit by Mexico seeking to hold American gun manufacturers responsible for facilitating the trafficking of weapons to drug cartels across the U.S.-Mexico border. The Boston-based 1st U.S. Circuit Court of Appeals overturned a lower-court judge’s decision dismissing the case on the grounds that a U.S. law barred Mexico from suing Smith & Wesson Brands, Sturm, Ruger & Co and others. That law, the federal Protection of Lawful Commerce in Arms Act (PLCAA), provides the firearms industry broad protection from …