Summary:
This extends the getAccessToken documentation so it can be picked
up by typedoc and published, and makes a few other tweaks along
the way prompted by a typescript/typedoc version change.
Test Plan: made in concert with a grist-help update
Reviewers: jarek
Reviewed By: jarek
Subscribers: jarek
Differential Revision: https://phab.getgrist.com/D3548