digitialio -document how to unset pullup/down

[ladyada]

https://circuitpython.readthedocs.io/en/latest/shared-bindings/digitalio/Pull.html

'None' is valid too! :)

[kevinjwalters]

Adafruit Learn: CircuitPython Basics: Digital Inputs & Outputs: Digital Inputs mentions digitalio.Pull.NONE. I put some feedback in as that does not exist and I'm not sure it ever has, it doesn't appear in CP 2 docs.

[dhalbert]

Adafruit Learn: CircuitPython Basics: Digital Inputs & Outputs: Digital Inputs mentions digitalio.Pull.NONE. I put some feedback in as that does not exist and I'm not sure it ever has, it doesn't appear in CP 2 docs.

Fixed in the guide. Thanks for spotting this.