Ticket 2204: Add docs for the updates icon

2204: Add docs for the updates icon

The text about the review request update notifications should also cover the favicon update. It should provide a picture of the icon.

#1 chipx86

+	Priority-Low

#2 chipx86

Pushing lower-priority docs to to 1.6.x.

+	Milestone-Release1.6.x

#3 david

This isn't really something that needs documentation because it's pretty self-explanatory.