class Rails::Command::ServerCommand

def rack_server_suggestion(server)
  if server.in?(RACK_SERVERS)
    <<~MSG
      Could not load server "#{server}". Maybe you need to the add it to the Gemfile?
        gem "#{server}"
      Run `bin/rails server --help` for more options.
    MSG
  else
    error = CorrectableError.new("Could not find server '#{server}'.", server, RACK_SERVERS)
    if error.respond_to?(:detailed_message)
      formatted_message = error.detailed_message
    else
      formatted_message = error.message
    end
    <<~MSG
      #{formatted_message}
      Run `bin/rails server --help` for more options.
    MSG
  end
end