Rename feature to G38_PROBE_TARGET

Marlin/Marlin.h

@@ -209,7 +209,7 @@ void manage_inactivity(bool ignore_stepper_queue = false);
 
 #endif // !MIXING_EXTRUDER
 
-#if ENABLED(G38_2_3)
+#if ENABLED(G38_PROBE_TARGET)
   extern bool G38_move,        // flag to tell the interrupt handler that a G38 command is being run
               G38_endstop_hit; // flag from the interrupt handler to indicate if the endstop went active
 #endif