clean up docs and provide defaults for keymap

keyboards/frosty_flake/frosty_flake.c

@@ -44,3 +44,20 @@ void led_set_kb(uint8_t usb_led) {
 
     led_set_user(usb_led);
 }
+
+__attribute__ ((weak))
+void matrix_init_user(void) {
+}
+
+__attribute__ ((weak))
+void matrix_scan_user(void) {
+}
+
+__attribute__ ((weak))
+bool process_record_user(uint16_t keycode, keyrecord_t *record) {
+  return true;
+}
+
+__attribute__ ((weak))
+void led_set_user(uint8_t usb_led) {
+}