[Doc] Use number indexes for encoder code example (#22980)

docs/feature_encoders.md

@@ -82,10 +82,10 @@ Your `keymap.c` will then need an encoder mapping defined (for four layers and t
 ```c
 #if defined(ENCODER_MAP_ENABLE)
 const uint16_t PROGMEM encoder_map[][NUM_ENCODERS][NUM_DIRECTIONS] = {
-    [_BASE] =   { ENCODER_CCW_CW(KC_MS_WH_UP, KC_MS_WH_DOWN), ENCODER_CCW_CW(KC_VOLD, KC_VOLU)  },
-    [_LOWER] =  { ENCODER_CCW_CW(RGB_HUD, RGB_HUI),           ENCODER_CCW_CW(RGB_SAD, RGB_SAI)  },
-    [_RAISE] =  { ENCODER_CCW_CW(RGB_VAD, RGB_VAI),           ENCODER_CCW_CW(RGB_SPD, RGB_SPI)  },
-    [_ADJUST] = { ENCODER_CCW_CW(RGB_RMOD, RGB_MOD),          ENCODER_CCW_CW(KC_RIGHT, KC_LEFT) },
+    [0] = { ENCODER_CCW_CW(KC_MS_WH_UP, KC_MS_WH_DOWN), ENCODER_CCW_CW(KC_VOLD, KC_VOLU)  },
+    [1] = { ENCODER_CCW_CW(RGB_HUD, RGB_HUI),           ENCODER_CCW_CW(RGB_SAD, RGB_SAI)  },
+    [2] = { ENCODER_CCW_CW(RGB_VAD, RGB_VAI),           ENCODER_CCW_CW(RGB_SPD, RGB_SPI)  },
+    [3] = { ENCODER_CCW_CW(RGB_RMOD, RGB_MOD),          ENCODER_CCW_CW(KC_RIGHT, KC_LEFT) },
 };
 #endif
 ```