Documentation: input: fix path to input code definitions

The UAPI header split failed to update the documentation for the input
event codes; fix things accordingly.
Signed-off-by: NMartin Kepplinger <martink@posteo.de>
Signed-off-by: NJonathan Corbet <corbet@lwn.net>

Documentation/input/input.txt

@@ -279,10 +279,10 @@ struct input_event {
 
   'time' is the timestamp, it returns the time at which the event happened.
 Type is for example EV_REL for relative moment, EV_KEY for a keypress or
-release. More types are defined in include/linux/input.h.
+release. More types are defined in include/uapi/linux/input-event-codes.h.
 
   'code' is event code, for example REL_X or KEY_BACKSPACE, again a complete
-list is in include/linux/input.h.
+list is in include/uapi/linux/input-event-codes.h.
 
   'value' is the value the event carries. Either a relative change for
 EV_REL, absolute new value for EV_ABS (joysticks ...), or 0 for EV_KEY for