Update Box3.html

added missing part of description (must have been copy-pasted from Box2)

docs/api/math/Box3.html

@@ -167,7 +167,7 @@
 			[page:Vector3 optionalTarget] — (optional) if specified, the result will be copied into this Vector3,
 			otherwise a new Vector3 will be created. <br /><br />
 
-		Returns the width and height of this box.
+		Returns the width, height and depth of this box.
 		</div>
 
 		<h3>[method:Box3 intersect]( [page:Box3 box] )</h3>