Add copilot docs to wire up a PAT for github api access

Update doc:
https://docs.github.com/en/rest?apiVersion=2026-03-10

With things from here:
https://github.com/settings/personal-access-tokens
https://docs.github.com/en/rest?apiVersion=2026-03-10

To walk through a github copilot api setup, i guess it would be in the 'custom' category, but a copilot category might be better so we do not have to guess what the URL's and other values are.