Typo in panSpeed description (#21703)

says "zoom" instead of "pan"

docs/examples/en/controls/TrackballControls.html

@@ -126,7 +126,7 @@
 
 		<h3>[property:Number panSpeed]</h3>
 		<p>
-			The zoom speed. Default is *0.3*.
+			The pan speed. Default is *0.3*.
 		</p>
 
 		<h3>[property:Number rotateSpeed]</h3>