🚸 M401 H - Report BLTouch HS State (#23724)

Marlin/src/gcode/probe/M401_M402.cpp

  * M401: Deploy and activate the Z probe
  *
  * With BLTOUCH_HS_MODE:
+ *  H       Report the current BLTouch HS mode state and exit
  *  S<bool> Set High Speed (HS) Mode and exit without deploy
  */
 void GcodeSuite::M401() {
-  if (parser.seen('S')) {
+  const bool seenH = parser.seen_test('H'),
+             seenS = parser.seen('S');
+  if (seenH || seenS) {
     #ifdef BLTOUCH_HS_MODE
-      bltouch.high_speed_mode = parser.value_bool();
+      if (seenS) bltouch.high_speed_mode = parser.value_bool();
+      SERIAL_ECHO_START();
+      SERIAL_ECHOPGM("BLTouch HS mode ");
+      serialprintln_onoff(bltouch.high_speed_mode);
     #endif
   }
   else {