docs: Add accelerometer range and units

[microbit-sam]

The measurement is given in milli-Newtons, for example +/- 2g will return +/- 2000mN.

[microbit-carlos]

As you mention, since the range of values will be dependent on the accelerometer sample range configured, could we add a short note about that relationship between the sample range and the range of values returned by these methods?

https://github.com/lancaster-university/microbit-dal/blob/v2.0.0-rc10/source/drivers/MicroBitAccelerometer.cpp#L263-L283

It's true that MicroPython doesn't currently expose a way to change it, so the default of 2g is used, but it would be useful to have in the docs in case the method is added.

Also looking at the DAL docs it sounds like the units is milli-g?

[microbit-sam]

👍

[microbit-carlos]

Thank you Sam!