comment what 'swapped' actually means

src/rp2_common/pico_audio_i2s/include/pico/audio_i2s.h

@@ -106,6 +106,8 @@ extern "C" {
 #define PICO_AUDIO_I2S_CLOCK_PIN_BASE 26
 #endif
 
+// The default order is CLOCK_PIN_BASE=LRCLK, CLOCK_PIN_BASE+1=BCLK
+// The swapped order is CLOCK_PIN_BASE=BCLK,  CLOCK_PIN_BASE+1=LRCLK
 #ifndef PICO_AUDIO_I2S_CLOCK_PINS_SWAPPED
 #define PICO_AUDIO_I2S_CLOCK_PINS_SWAPPED 0
 #endif