simplify more

Marlin/src/gcode/control/T.cpp

@@ -41,16 +41,16 @@
  *   S1           Don't move the tool in XY after change
  *
  * For PRUSA_MMU2(S) and EXTENDABLE_EMU_MMU2(S)
- *   T[n] Gcode to extrude at least 38.10 mm at feedrate 19.02 mm/s must follow immediately to load to extruder wheels.
- *   T?   Gcode to extrude shouldn't have to follow. Load to extruder wheels is done automatically.
+ *   T[n] G-code to extrude at least 38.10 mm at feedrate 19.02 mm/s must follow immediately to load to extruder wheels.
+ *   T?   G-code to extrude shouldn't have to follow. Load to extruder wheels is done automatically.
  *   Tx   Same as T?, but nozzle doesn't have to be preheated. Tc requires a preheated nozzle to finish filament load.
  *   Tc   Load to nozzle after filament was prepared by Tc and nozzle is already heated.
  */
 void GcodeSuite::T(const int8_t tool_index) {
 
   #if HAS_MULTI_EXTRUDER
     // For 'T' with no parameter report the current tool.
-    if (tool_index == 255) {
+    if (parser.string_arg && *parser.string_arg == '*') {
       SERIAL_ECHOLNPGM(STR_ACTIVE_EXTRUDER, active_extruder);
       return;
     }

Marlin/src/gcode/parser.cpp

@@ -191,9 +191,9 @@ void GCodeParser::parse(char *p) {
       // Bail if there's no command code number
       if (!TERN(SIGNED_CODENUM, NUMERIC_SIGNED(*p), NUMERIC(*p))) {
         if (TERN0(HAS_MULTI_EXTRUDER, letter == 'T')) {
-          p[0] = '2'; p[1] = '5'; p[2] = '5'; p[3] = '\0'; // Convert 'T' alone into T255
+          *p = '*'; string_arg = p; // Convert 'T' alone into 'T*'
         }
-        else return;
+        return;
       }
 
       // Save the command letter at this point