In the rich text editor:
@neomblue
In a comment:
[neomblue](https://chowlings.com/user/neomblue)
For Names and Avatars:
In the rich text editor:
%neomblue
In a comment:
[](https://chowlings.com/user/neomblue) [neomblue](https://chowlings.com/user/neomblue)