cleanup: Require "dangling" commas

Since ES5, trailing commas in arrays and object literals are valid.
We generally haven't used them so far, but they are actually a good
idea, as they make additions and removals in diffs much cleaner.

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

js/ui/boxpointer.js

@@ -108,7 +108,7 @@ var BoxPointer = GObject.registerClass({
                 this._muteInput = false;
                 if (onComplete)
                     onComplete();
-            }
+            },
         });
     }
 
@@ -156,7 +156,7 @@ var BoxPointer = GObject.registerClass({
                 this.translation_y = 0;
                 if (onComplete)
                     onComplete();
-            }
+            },
         });
     }