AnimationUtils: Fix typo in docs.

Author: Don McCurdy

docs/api/en/animation/AnimationUtils.html

@@ -49,7 +49,7 @@ <h3>[method:Boolean isTypedArray]( object )</h3>
 		Returns *true* if the object is a typed array.
 		</p>
 
-		<h3>[method:AnimationClip mergeMorphTargetTracks]( [param:AnimationClip tracks], [param:Object3D root] )</h3>
+		<h3>[method:AnimationClip mergeMorphTargetTracks]( [param:AnimationClip clip], [param:Object3D root] )</h3>
 		<p>
 		Merges all KeyframeTracks that animate morph targets on a single mesh. The clip provided will
 		be modified and returned.

docs/api/zh/animation/AnimationUtils.html

@@ -47,7 +47,7 @@ <h3>[method:Boolean isTypedArray]( object )</h3>
 
 		</p>
 
-		<h3>[method:AnimationClip mergeMorphTargetTracks]( [param:AnimationClip tracks], [param:Object3D root] )</h3>
+		<h3>[method:AnimationClip mergeMorphTargetTracks]( [param:AnimationClip clip], [param:Object3D root] )</h3>
 		<p></p>
 
 		<h3>[method:Array sortedArray]( values, stride, order )</h3>