As far as I can tell, ime.h is only included by the x11 keyboard driver and `WM_IMEKEYDOWN` and `WM_IMEKEYUP` are not used there, so this change should only bring the naming convention in line with what is already in winuser and MSDN.
-- v3: winex11: Do not include ime.h. include: Add Japanese IME virtual key codes to winuser.rh.