Update Stream: Tagging transparency

Not tagging a person on a update and going back and relying to that comment a week later makes it look like the person has been tagged on both comments.

It allow a person to come back and say"this person was tagged the whole time"

The user should know exactly who was tagged on each individual comment. This will hold people accountable foe tagging the appropriate people at the time of the comment.

Attached a snapshot from a ticket I opened. Was asked to put this into Idea Exchange but I think that 18.1 release and before worked differently then it does in 18.2