cleanup: Only omit braces for single-line blocks

Braces can be avoided when a block consists of a single statement,
but readability suffers when the statement spans more than a single
line.

https://gitlab.gnome.org/GNOME/gnome-shell/merge_requests/805

js/ui/status/thunderbolt.js

@@ -199,9 +199,10 @@ var AuthRobot = class {
          */
         this._enrolling = this._devicesToEnroll.length > 0;
 
-        if (this._enrolling)
+        if (this._enrolling) {
             GLib.idle_add(GLib.PRIORITY_DEFAULT,
                           this._enrollDevicesIdle.bind(this));
+        }
     }
 
     _enrollDevicesIdle() {