Fix MediaStyle API comments

     * <pre class="prettyprint">

     * Notification noti = new Notification.Builder()

     *     .setSmallIcon(R.drawable.ic_stat_player)

     *     .setContentTitle("Track title")     // these three lines are optional

     *     .setContentText("Artist - Album")   // if you use

     *     .setLargeIcon(albumArtBitmap))      // setMediaSession(token)

     *     .setContentTitle("Track title")

     *     .setContentText("Artist - Album")

     *     .setLargeIcon(albumArtBitmap))

     *     .setStyle(<b>new Notification.MediaStyle()</b>

     *         .setMediaSession(mySession))

     *     .build();