Contributing to website

[alustig3]

I think it would be useful to add a link to this repository's issues on the contributing page.

So in addition to:

Have an idea for a new driver or library? File an issue on the CircuitPython repo!

There would also be something like:

Have an idea or correction for this website? File an issue on the circuitpython.org repo!

[makermelissa]

Something that points to https://learn.adafruit.com/how-to-add-a-new-board-to-the-circuitpython-org-website would probably be useful as well.