Make default layer size 16-bit (#15286)

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

layouts/community/ergodox/kastyle/keymap.c

@@ -1,5 +1,5 @@
 /* Setup to approximate a Kinesis Advantage with an eye to use in a
- * Mac/OSX environment 
+ * Mac/OSX environment
  * This version adds a hand swap feature to flip the keyboard */
 #include QMK_KEYBOARD_H
 #include "debug.h"
@@ -143,7 +143,7 @@ LAYOUT_ergodox(
 // Runs constantly in the background, in a loop.
 void matrix_scan_user(void) {
 
-    uint8_t layer = biton32(layer_state);
+    uint8_t layer = get_highest_layer(layer_state);
 
     ergodox_board_led_off();
     ergodox_right_led_1_off();