add note to makefile for future use

Makefile

@@ -304,6 +304,7 @@ define PARSE_KEYBOARD
     KEYMAPS += $$(notdir $$(patsubst %/.,%,$$(wildcard $(ROOT_DIR)/keyboards/$$(KEYBOARD_FOLDER_PATH_3)/keymaps/*/.)))
     KEYMAPS += $$(notdir $$(patsubst %/.,%,$$(wildcard $(ROOT_DIR)/keyboards/$$(KEYBOARD_FOLDER_PATH_4)/keymaps/*/.)))
     KEYMAPS += $$(notdir $$(patsubst %/.,%,$$(wildcard $(ROOT_DIR)/keyboards/$$(KEYBOARD_FOLDER_PATH_5)/keymaps/*/.)))
+    # this might be needed, but in a different form
     #KEYMAPS := $$(sort $$(filter-out $$(KEYBOARD_FOLDER_1) $$(KEYBOARD_FOLDER_2) \
         $$(KEYBOARD_FOLDER_3) $$(KEYBOARD_FOLDER_4) $$(KEYBOARD_FOLDER_5), $$(KEYMAPS)))