feat(midi): add more commentaries

Author: SuGlider

cores/esp32/Arduino.h

@@ -223,6 +223,13 @@ size_t getArduinoLoopTaskStackSize(void);
   }
 
 #define ESP32_USB_MIDI_DEFAULT_NAME "TinyUSB MIDI"
+/**
+* @brief Set the current device name
+* 1. Name set via constructor (if any)
+* 2. Name set via SET_USB_MIDI_DEVICE_NAME() macro (if defined)
+* 3. Default name "TinyUSB MIDI"
+* If device name is set as "", it will be ignored
+*/
 #define SET_USB_MIDI_DEVICE_NAME(name)        \
   const char* getUSBMIDIDefaultDeviceName() { \
     if (strlen(name) == 0) {                  \