Add documentation for the Potentiometer module included with KMK

[NiceManiac]

KMK includes a potentiometer module, potentiometer.py, but this does not have any documentation. i have written up some basic documentation for this module after some digging and reverse engineering, to help people who are not as persistent as me.

[xs5871]

First off: thank you so much for taking the time to add to the documentation. That's one of our weak points, and it's very appreciated.

This is where I see a problem:
The potentiometer code is kind of old, a bit weird, should really have a different name (and cover all continuous / ADC peripherals); and the examples in your documentation use interfaces that are likely to be deprecated soonish.
I don't want to just throw away your work, not only because it's obviously covering some of our blind spots, but also because some of that example code may have a place in a hypothetical "proper" analog module. I also don't want to merge something that I know I have to completely rewrite at some point.

If you're up for a dive and want to help me improve our handling of analog peripherals, that'd be awesome.
If not, we can discuss just the doc contribution and get a bit polished and somewhat more future proof.

[NiceManiac]

The potentiometer module is a bit weird, but it does work at least for now for analog signals, even if it relies on deprecated code to make it run.
I do agree that the module probably should be renamed, maybe to analog or something similar as it does apply to any analog signal coming thru the ADC ports.
I mainly just wanted to write down my findings in case anyone else was interested in getting potentiometers to work with KMK, although i am still trying to work out a good way to add a controller HID device to be able to also output analog data as controller joysticks to the pc.
As for improving the handling of analog signals i will have to do some reading on how circuitpython handles analog signals, which at the moment i don't really have time to get fully educated on, but in the meantime i think that we should be able to get the doc contribution into a useful state. as i have stated i havent analyzed the entire codebase so my writeup only included what i have managed to figure out from my evening hairpulling while trying to get my board to do what i wanted. Ofc if there is any newer features that might improve the way the module works i would be really interested in learning more about how KMK works, and also improving the documentation.

[xs5871]

That sounds great. Give me a couple of days to give this a proper look at. We may have to change the pot module a tiny bit to get to an MVP.