message: Add missing entry to VS generators
diff: @@ -598,7 +598,8 @@ const VsGenerators: {[key: string]: string} = {
  12: 'Visual Studio 12 2013',
  VS140COMNTOOLS: 'Visual Studio 14 2015',
  14: 'Visual Studio 14 2015',
  - 15: 'Visual Studio 15 2017'
  + 15: 'Visual Studio 15 2017',
  + 16: 'Visual Studio 16 2019'
  };
  async function varsForVSInstallation(inst: VSInstallation, arch: string): Promise<Map<string, string>|null> {
  