fix typo

voice.go

@@ -570,7 +570,7 @@ func (v *VoiceConnection) udpOpen() (err error) {
 		return fmt.Errorf("received udp packet too small")
 	}
 
-	// Loop over position 4 though 20 to grab the IP address
+	// Loop over position 4 through 20 to grab the IP address
 	// Should never be beyond position 20.
 	var ip string
 	for i := 4; i < 20; i++ {