M915 Incorrect stall detection range for TMC2209 drivers

[gloomyandy]

Hi,
I've just noticed that the M915 documentation has...

Snnn Stall detection threshold (-64 to +63, values below -10 not recommended). Lower values make stall detection more sensitive. S3 is a good starting point for many motors.

However boards that use the TMC2209 device actually accept a value that has a range of -128 to +127 see: https://github.com/Duet3D/RepRapFirmware/blob/3.4-dev/src/Movement/StepperDrivers/TMC22xx.cpp#L996

You might also want to update the references to TMC2660 and TMC2130 to also include TMC2209 and TMC5160 (and possibly other devices if you have boards that include them).

[droftarts]

@gloomyandy Thanks, updated. It was getting a bit long winded, so I moved the parameter description to a note.

Ian