Clarifiying Documentation Links

Summary: Fixes T8487.

Test Plan: Verify that links are clear at Diviner > Phabricator Contributor Docs > Using the Phabricator OAuth Server.

Reviewers: lpriestley, Blessed Reviewers, epriestley

Reviewed By: Blessed Reviewers, epriestley

Subscribers: epriestley, Korvin

Maniphest Tasks: T8487

Differential Revision: https://secure.phabricator.com/D13240