Updated comment after 776d1bebdca2.

src/http/ngx_http_request.h

@@ -510,7 +510,7 @@ struct ngx_http_request_s {
     /*
      * instead of using the request context data in
      * ngx_http_limit_conn_module and ngx_http_limit_req_module
-     * we use the single bits in the request structure
+     * we use the bit fields in the request structure
      */
     unsigned                          limit_conn_set:1;
     unsigned                          limit_req_status:3;