✨ Support for up to 9 axes (linear, rotary) (#23112)

Co-authored-by: Scott Lahteine <thinkyhead@users.noreply.github.com>

Marlin/src/gcode/calibrate/M666.cpp

@@ -44,7 +44,7 @@
   void GcodeSuite::M666() {
     DEBUG_SECTION(log_M666, "M666", DEBUGGING(LEVELING));
     bool is_err = false, is_set = false;
-    LOOP_LINEAR_AXES(i) {
+    LOOP_NUM_AXES(i) {
       if (parser.seen(AXIS_CHAR(i))) {
         is_set = true;
         const float v = parser.value_linear_units();