By Steve Holland and Jarrett Renshaw NEW YORK (Reuters) -U.S. President Joe Biden highlighted his administration’s efforts to curb gun violence during a visit to New York City also aimed at projecting a united front with Mayor Eric Adams after a series of violent crimes that has rattled the city. Biden and U.S. Attorney General Merrick Garland made the trip in the wake of the funerals of two city police officers who were fatally shot last month while responding to a 911 call. The police killings are part of an overall surge in gun violence in U.S. cities, including Philadelphia and Chicago, si…