Fix boundary in `RGB_MATRIX_INDICATOR_SET_COLOR` (#18650)

docs/feature_rgb_matrix.md

@@ -912,7 +912,7 @@ Caps Lock indicator on alphanumeric flagged keys:
 ```c
 bool rgb_matrix_indicators_advanced_user(uint8_t led_min, uint8_t led_max) {
     if (host_keyboard_led_state().caps_lock) {
-        for (uint8_t i = led_min; i <= led_max; i++) {
+        for (uint8_t i = led_min; i < led_max; i++) {
             if (g_led_config.flags[i] & LED_FLAG_KEYLIGHT) {
                 rgb_matrix_set_color(i, RGB_RED);
             }
@@ -925,7 +925,7 @@ bool rgb_matrix_indicators_advanced_user(uint8_t led_min, uint8_t led_max) {
 Layer indicator on all keys:
 ```c
 bool rgb_matrix_indicators_advanced_user(uint8_t led_min, uint8_t led_max) {
-    for (uint8_t i = led_min; i <= led_max; i++) {
+    for (uint8_t i = led_min; i < led_max; i++) {
         switch(get_highest_layer(layer_state|default_layer_state)) {
             case 2:
                 rgb_matrix_set_color(i, RGB_BLUE);
@@ -951,7 +951,7 @@ bool rgb_matrix_indicators_advanced_user(uint8_t led_min, uint8_t led_max) {
             for (uint8_t col = 0; col < MATRIX_COLS; ++col) {
                 uint8_t index = g_led_config.matrix_co[row][col];
 
-                if (index >= led_min && index <= led_max && index != NO_LED &&
+                if (index >= led_min && index < led_max && index != NO_LED &&
                 keymap_key_to_keycode(layer, (keypos_t){col,row}) > KC_TRNS) {
                     rgb_matrix_set_color(index, RGB_GREEN);
                 }
@@ -983,7 +983,7 @@ bool rgb_matrix_indicators_advanced_user(uint8_t led_min, uint8_t led_max) {
     }
     RGB rgb = hsv_to_rgb(hsv);
 
-    for (uint8_t i = led_min; i <= led_max; i++) {
+    for (uint8_t i = led_min; i < led_max; i++) {
         if (HAS_FLAGS(g_led_config.flags[i], 0x01)) { // 0x01 == LED_FLAG_MODIFIER
             rgb_matrix_set_color(i, rgb.r, rgb.g, rgb.b);
         }

quantum/rgb_matrix/rgb_matrix.h

@@ -81,7 +81,7 @@
 #endif
 
 #define RGB_MATRIX_INDICATOR_SET_COLOR(i, r, g, b) \
-    if (i >= led_min && i <= led_max) {            \
+    if (i >= led_min && i < led_max) {             \
         rgb_matrix_set_color(i, r, g, b);          \
     }