Branching off from this suggestion made in #18742.

Links that open in a new tab or window need to be communicated as such to all users in an accessible way.

In particular, we want the alert to be perceived by all users (not just screen reader users) and such to be non-obtrusive to users who are sensitive to content overload and repetition.

It was suggested to use the already common practice of adding an icon next to the link and in addition to follow this accessible example from Inclusive Components for accessible tooltips. We think this approach will get us what we need.