Todo
The show-hit addon of CodeMirror library can be used. User data array can be populated with an API endpoint. Autocomplete list can be triggered with @ character.
What is expected
Allura user can hit "@" character and get the autocomplete list to select a user for mentioning. once an user is selected from the autocomplete list, the username will be added with "@" Eg:- @admin1
feedback on https://forge-allura.apache.org/p/allura/git/merge-requests/327/