Fix Per Key LED Indicator Callbacks (#18450)

Co-authored-by: Dasky <[email protected]>
Co-authored-by: Nick Brassel <[email protected]>

docs/feature_led_matrix.md

@@ -441,8 +441,12 @@ Where `28` is an unused index from `eeconfig.h`.
 
 If you want to set custom indicators, such as an LED for Caps Lock, or layer indication, you can use the `led_matrix_indicators_kb` or `led_matrix_indicators_user` function for that: 
 ```c
-void led_matrix_indicators_kb(void) {
+bool led_matrix_indicators_kb(void) {
+    if (!led_matrix_indicators_user()) {
+        return false;
+    }
     led_matrix_set_value(index, value);
+    return true;
 }
 ```
 
@@ -451,5 +455,6 @@ In addition, there are the advanced indicator functions.  These are aimed at tho
 ```c
 void led_matrix_indicators_advanced_user(uint8_t led_min, uint8_t led_max) {
     LED_MATRIX_INDICATOR_SET_VALUE(index, value);
+    return false;
 }
 ```