DefaultLEDModeConfig: Fix a typo in the documentation

The example in the documentation was referring to a function that does not
exist. Correct it to use the one that does.

Signed-off-by: Gergely Nagy <algernon@keyboard.io>

plugins/Kaleidoscope-DefaultLEDModeConfig/README.md

@@ -31,7 +31,7 @@ KALEIDOSCOPE_INIT_PLUGINS(EEPROMSettings,
 void setup() {
   Kaleidoscope.setup();
 
-  DefaultLEDModeConfig.activeLEDModeIfUnconfigured(
+  DefaultLEDModeConfig.activateLEDModeIfUnconfigured(
     &LEDRainbowWaveEffect
   );
 }