Add Planner::sync_from_steppers

Use to sync the planner after an interrupted move (when not overriding
the logical position).

Marlin/planner.cpp

@@ -1210,6 +1210,13 @@ void Planner::set_position_mm(ARG_X, ARG_Y, ARG_Z, const float &e) {
   LOOP_XYZE(i) previous_speed[i] = 0.0;
 }
 
+/**
+ * Sync from the stepper positions. (e.g., after an interrupted move)
+ */
+void Planner::sync_from_steppers() {
+  LOOP_XYZE(i) position[i] = stepper.position((AxisEnum)i);
+}
+
 /**
  * Directly set the planner E position (hence the stepper E position).
  */