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/workspaceThumbnail.js

@@ -1204,11 +1204,12 @@ var ThumbnailsBox = GObject.registerClass({
     }
 
     _updatePorthole() {
-        if (!Main.layoutManager.primaryMonitor)
+        if (!Main.layoutManager.primaryMonitor) {
             this._porthole = { width: global.stage.width, height: global.stage.height,
                                x: global.stage.x, y: global.stage.y };
-        else
+        } else {
             this._porthole = Main.layoutManager.getWorkAreaForMonitor(Main.layoutManager.primaryIndex);
+        }
 
         this.queue_relayout();
     }