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