fix copy-paste error: 2D => 3D

docs/api/math/Box3.html

@@ -280,7 +280,7 @@
 		[page:Vector3 offset] - Direction and distance of offset.<br /><br />
 
 		Adds [page:Vector3 offset] to both the upper and lower bounds of this box, effectively moving this box
-		[page:Vector3 offset] units in 2D space.
+		[page:Vector3 offset] units in 3D space.
 		</div>
 
 		<h3>[method:Box3 union]( [page:Box3 box] )</h3>