Follow-up from "Updates roles to match incident.io, reorganizes content"

The following discussion from !16528 (merged) should be addressed:

• @sarahwalker started a discussion: (+1 comment)

  I believe the :pushpin: emoji will post a public update, and the :star: emoji is used for a confidential (internal) update

@sabrams - is Sarah right? Do we have the documentation incorrect on the incident page?