Fix nyquist (and other splits using D2 in debouncing) (#3067)

* Update default Nyquist revision

* LED slave fix

* Sync changes from lets_split

* Add needed check for debouncing

* Remove line that was setting PD2 pin and interfering with use of that pin

* Add backlight key to keymap

keyboards/lets_split/matrix.c

@@ -157,7 +157,6 @@ uint8_t _matrix_scan(void)
             if (matrix_changed) {
                 debouncing = true;
                 debouncing_time = timer_read();
-                PORTD ^= (1 << 2);
             }
 
 #       else