Fixed minor error in doc

docs/api/lights/RectAreaLight.html

@@ -96,7 +96,7 @@ scene.add(rectLight)
 
 		<h3>[property:Boolean isRectAreaLight]</h3>
 		<div>
-			Used to check whether this or derived classes are spot lights. Default is *true*.<br /><br />
+			Used to check whether this or derived classes are RectAreaLights. Default is *true*.<br /><br />
 
 			You should not change this, as it used internally for optimisation.
 		</div>