Worng command code for numTrack USB and TF

[khoemachteam]

Hi,

There is an issue at
@brief Determine the number of tracks accessible via USB.
@return Number of tracks accessible via USB, -1 if error.
*/
/**************************************************************************/
int16_t DFPlayerMini_Fast::numUsbTracks()
{
return query(dfplayer::GET_TF_FILES);
}

and

//
/*!
@brief Determine the number of tracks accessible via SD card.
@return Number of tracks accessible via SD card, -1 if error.
*/
//
int16_t DFPlayerMini_Fast::numSdTracks()
{
return query(dfplayer::GET_U_FILES);
}

it should be GET_U_FILES for numUsbTracks() and GET_TF_FILES for numSdTracks

please check.

Thanks