Component that will be displayed when user tries to mention other user (by typing @ in chatbar).
Currently, it is not created anywhere, but code that does it will be added in next diffs.
Component takes list of actions and it's absolute position that will be calculated outside of it.
Notice it isn't positioned correctly yet, as it's work in progress.
Relevant linear tasks:
https://linear.app/comm/issue/ENG-2096/typeahead-in-tooltip-for-mentions
https://linear.app/comm/issue/DES-1/design-typeahead-for-mentions-on-web#comment-f40bb8c5