A critical race in the battle for control of the Virginia Senate has entered a new dimension for state legislative races with a national gun-control group’s announcement that it is buying $700,000 of political advertisements for Democrat Daniel A. Gecker in his race for the 10th District seat in Richmond and its suburbs. Everytown for Gun Safety Action Fund, backed by former New York Mayor Michael Bloomberg, said Wednesday it will begin airing a television ad today in the Richmond media market that features the father of Alison Parker, a 24-year-old Roanoke television reporter gunned down with her cameraman, Adam...