Fixed a typo in the documentation of TransformControls (#23718)

docs/examples/en/controls/TransformControls.html

@@ -153,7 +153,7 @@
 
 		<h3>[method:TransformControls detach] ()</h3>
 		<p>
-			Removes the current 3D object from the controls and makes the helper UI is invisible.
+			Removes the current 3D object from the controls and makes the helper UI invisible.
 		</p>
 
 		<h3>[method:undefined dispose] ()</h3>