Update SkinnedMesh.html (#21561)

* Update SkinnedMesh.html

* Update SkinnedMesh.html

Author: prominentdetail

docs/api/en/objects/SkinnedMesh.html

@@ -153,6 +153,11 @@ <h3>[method:null updateMatrixWorld]( [param:Boolean force] )</h3>
 		Updates the [page:Matrix4 MatrixWorld].
 		</p>
 
+		<h3>[method:Vector3 boneTransform]( [index:Integer], [target:Vector3] )</h3>
+		<p>
+		Calculates the position of the vertex at the given index relative to the current bone transformations.
+		</p>
+			
 		<h2>Source</h2>
 
 		<p>