Add schema prefix examples to watch folder field descriptions

Latest update does the following at the job-configuration level now:

          $watch_folder_path = $config->field_watch_config_folder[$config->language][0]['value'];
          $scheme = file_uri_scheme($watch_folder_path);
          if (!file_stream_wrapper_valid_scheme($scheme)) {
            $watch_folder_path = file_build_uri($watch_folder_path);
          }
          $job->field_orig_watch_config_folder[$job->language][0]['value'] = $watch_folder_path;

That way it will take URLs in both formats - with and without schema.