if you could 'tag' a person in a comment in an Issue.

e.g. if an Issue is assigned to me, but I need to ask a colleague for input, it would be great if I could tag the colleague.
I am aware of the function in the comment where you can type "@xxx@xxx.xx" but it would be very helpful, faster and easier if you could type '@' and find the person from the same dropdown as when assigning the Issue.