message: Autocomplete: check if first argument is "install"
diff: namespace vcpkg::Commands::Autocomplete
  {
  + std::vector<std::string> autocomplete_install(
  + const std::vector<std::unique_ptr<SourceControlFile>>& source_paragraphs, const std::string& start_with)
  + {
  + std::vector<std::string> results;
  + const auto& istartswith = Strings::case_insensitive_ascii_starts_with;
  +
  + for (const auto& source_control_file : source_paragraphs)
  + {
  + auto&& sp = *source_control_file->core_paragraph;
  +
  + if (istartswith(sp.name, start_with))
  + {
  + results.push_back(sp.name);
  + }
  + }
  + return results;
  + }
  void perform_and_exit(const VcpkgCmdArguments& args, const VcpkgPaths& paths)
  {
  static const std::string EXAMPLE =
  @@ -21,27 +38,15 @@ namespace vcpkg::Commands::Autocomplete
  const std::string requested_command = args.command_arguments.at(0);
  const std::string start_with =
  args.command_arguments.size() > 1 ? args.command_arguments.at(1) : Strings::EMPTY;
  -
  - auto sources_and_errors = Paragraphs::try_load_all_ports(paths.get_filesystem(), paths.ports);
  - auto& source_paragraphs = sources_and_errors.paragraphs;
  -
  - const auto& istartswith = Strings::case_insensitive_ascii_starts_with;
  -
  std::vector<std::string> results;
  - for (const auto& source_control_file : source_paragraphs)
  + if (requested_command == "install")
  {
  - auto&& sp = *source_control_file->core_paragraph;
  + auto sources_and_errors = Paragraphs::try_load_all_ports(paths.get_filesystem(), paths.ports);
  + auto& source_paragraphs = sources_and_errors.paragraphs;
  - if (istartswith(sp.name, start_with))
  - {
  - results.push_back(sp.name);
  - }
  + results = autocomplete_install(source_paragraphs, start_with);
  }
  -
  System::println(Strings::join(" ", results));
  -
  - auto all_ports = Paragraphs::try_load_all_ports(paths.get_filesystem(), paths.ports);
  -
  Checks::exit_success(VCPKG_LINE_INFO);
  }
  }
  