Make default layer size 16-bit (#15286)

Co-authored-by: James Young <18669334+noroadsleft@users.noreply.github.com>

keyboards/biacco42/ergo42/keymaps/hdbx/keymap.c

@@ -134,7 +134,7 @@ const uint16_t PROGMEM keymaps[][MATRIX_ROWS][MATRIX_COLS] = {
 };
 
 // RGB Underglow使用時のレイヤー毎のカラー切り替え
-uint32_t layer_state_set_keymap (uint32_t state) {
+layer_state_t layer_state_set_keymap (layer_state_t state) {
   return state;
 }
 
@@ -148,7 +148,7 @@ void matrix_init_user(void) {
 layer_state_t layer_state_set_user(layer_state_t state) {
   state = update_tri_layer_state(state, _RAISE, _LOWER, _ADJUST);
 #ifdef RGBLIGHT_ENABLE
-    switch (biton32(state)) {
+    switch (get_highest_layer(state)) {
     case _RAISE:
       rgblight_setrgb_chartreuse(); // RAISE:シャルトリューズ
       break;