Associate event definitions with their EventHandler container

As done by other specs

Author: dontcallmedom

css-animations-1/Overview.bs

@@ -919,7 +919,7 @@ Types of <code>AnimationEvent</code></h3>
 
 	The different types of animation events that can occur are:
 
-	<dl dfn-type=event dfn-for=animationevent>
+	<dl dfn-type=event dfn-for=GlobalEventHandlers>
 		<dt><dfn>animationstart</dfn>
 		<dd>
 			The {{animationstart}} event occurs at the start of the animation.

css-transitions-1/Overview.bs

@@ -1141,7 +1141,7 @@ Types of <code>TransitionEvent</code> {#event-transitionevent}
 
 The different types of transition events that can occur are:
 
-  <dl dfn-type=event dfn-for=transitionevent>
+  <dl dfn-type=event dfn-for=GlobalEventHandlers>
     <dt><dfn id=transitionrun>transitionrun</dfn></dt>
     <dd>
       The {{transitionrun}} event occurs when a transition is created (i.e.,