Update AudioEffectChorus documentation

gui/index.html

@@ -2294,7 +2294,7 @@ The actual packets are taken
 	the original voice (so, 2 and up to get a chorus effect, although you can
 	specify 1 if you want).
 	</p>
-	<p class=func><span class=keyword>modify</span>(n_chorus);</p>
+	<p class=func><span class=keyword>voices</span>(n_chorus);</p>
 	<p class=desc>Alters the number of voices in a running chorus (previously started with begin).
 	</p>
 	<h3>Examples</h3>