Fix integralPromotion optional arg syntax: use ?width not ?(width:int option=None)

Co-authored-by: michael-schwarz <13812333+michael-schwarz@users.noreply.github.com>
Agent-Logs-Url: https://github.com/goblint/cil/sessions/b375cb35-22a8-482e-9239-4b1def60eb18

Author: Copilot

src/frontc/cabs2cil.ml

@@ -1359,7 +1359,7 @@ type condExpRes =
   | CENot of condExpRes
 
 (******** CASTS *********)
-let rec integralPromotion ?(width : int option = None) (t : typ) : typ = (* c.f. ISO 6.3.1.1 *)
+let rec integralPromotion ?width (t : typ) : typ = (* c.f. ISO 6.3.1.1 *)
   let int_bits = bitsSizeOf (TInt (IInt, [])) in
   match unrollType t with
     TInt (IBool, a) -> TInt (IInt, a) (* _Bool can only be 0 or 1, irrespective of its size *)