docs: Note stealthchop_threshold doesn't impact sensorless homing

Reported by @paulfertser.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

docs/TMC_Drivers.md

@@ -83,6 +83,10 @@ setting `stealthchop_threshold` to 999999). Unfortunately, the drivers
 often produce poor and confusing results if the mode changes while the
 motor is at a non-zero velocity.
 
+Note that the `stealthchop_threshold` config option does not impact
+sensorless homing as Klipper automatically switches the TMC driver to
+an appropriate mode during sensorless homing operations.
+
 ## TMC interpolate setting introduces small position deviation
 
 The TMC driver `interpolate` setting may reduce the audible noise of