Updated FAQ (markdown)

FAQ.md

@@ -63,7 +63,8 @@ Use `KC_PWR` instead of `KC_POWER` or vice versa.
 
 http://geekhack.org/index.php?topic=14290.msg1327264#msg1327264
 
-
+## Oneshot modifier
+https://github.com/tmk/tmk_keyboard/issues/71
 
 # Degug Console
 ## hid_listen can't find device