Log more info on ZMK config dir usage.

app/cmake/zmk_config.cmake

@@ -45,9 +45,11 @@ set(CACHED_ZMK_CONFIG ${ZMK_CONFIG} CACHE STRING "Selected user ZMK config")
 
 if (ZMK_CONFIG)
 	if(EXISTS "${ZMK_CONFIG}/boards")
+		message(STATUS "Adding ZMK config directory as board root: ${ZMK_CONFIG}")
 		list(APPEND BOARD_ROOT "${ZMK_CONFIG}")
 	endif()
 	if(EXISTS "${ZMK_CONFIG}/dts")
+		message(STATUS "Adding ZMK config directory as DTS root: ${ZMK_CONFIG}")
 		list(APPEND DTS_ROOT "${ZMK_CONFIG}")
 	endif()
 endif()