🎨 Macros for optional arguments (#21969)

Marlin/src/feature/fwretract.cpp

@@ -91,11 +91,7 @@ void FWRetract::reset() {
  * Note: Auto-retract will apply the set Z hop in addition to any Z hop
  *       included in the G-code. Use M207 Z0 to to prevent double hop.
  */
-void FWRetract::retract(const bool retracting
-  #if HAS_MULTI_EXTRUDER
-    , bool swapping/*=false*/
-  #endif
-) {
+void FWRetract::retract(const bool retracting OPTARG(HAS_MULTI_EXTRUDER, bool swapping/*=false*/)) {
   // Prevent two retracts or recovers in a row
   if (retracted[active_extruder] == retracting) return;