Add scary warnings about the esp32CustomAdvanced env

platformio.ini

@@ -153,6 +153,8 @@ lib_deps =
 build_type = debug
 
 [env:esp32CustomAdvanced]
+; For non-chainlink custom ESP32-based advanced builds that use shift registers but omit the Chainlink design elements like loopbacks and LEDs.
+; This is not the environment you want unless you have custom non-Chainlink hardware and really know the intricacies of the shift register arrangement.
 extends=esp32base
 build_flags =
     ${esp32base.build_flags}