fix comment

src/Webapi/Webapi__Dom/Webapi__Dom__BeforeUnloadEvent.re

@@ -8,6 +8,6 @@ include Webapi__Dom__Event.Impl({ type nonrec t = t; });
 [@bs.get] external returnValue : t => string = "";
 /**
  * returnValue cannot be unset because BS cannot (afaik) bind `delete e['returnValue'];`
- * Setting the value to undefined does not either.
+ * Setting the value to undefined does not cause expected behavior.
  */
 [@bs.set] external setReturnValue: (t, string) => unit = "returnValue";