Document all packages and peripherals about esp-hal

[jessebraham]

@IshanDaga if you are willing to work on this then yes, that would be awesome! This is definitely one of our weaker points currently so it'd be great to improve this.

In general (with the exception of the chip support label) any open issue is fair game; if it's assigned to somebody already just ask if they're actively working on it, there's a good chance they are not and that you can take it over 😁

[IshanDaga]

Hi Jesse,
New to Rust, though I have been using the ESP-IDF for the last 15 or so months.

I'd like to be able to contribute to this project and learn rust while I'm at it - is this a good place to start?

[jessebraham]

I've documented the Rng peripheral in #650, which can be loosely used as a model for other peripherals. @playfulFence is also working on a number of drivers' documentation.

[jessebraham]

With #680 merged I'm happy to call this "done". There is of course more work to do, but all packages and modules have at least some documentation now.