Patch sync_plan_position comment

Marlin/Marlin_main.cpp

@@ -645,9 +645,9 @@ static void report_current_position();
 
 /**
  * sync_plan_position
- * Set planner / stepper positions to the cartesian current_position.
- * The stepper code translates these coordinates into step units.
- * Allows translation between steps and millimeters for cartesian & core robots
+ *
+ * Set the planner/stepper positions directly from current_position with
+ * no kinematic translation. Used for homing axes and cartesian/core syncing.
  */
 inline void sync_plan_position() {
   #if ENABLED(DEBUG_LEVELING_FEATURE)