In the rich text editor:
@SourBugs
In a comment:
[SourBugs](https://chowlings.com/user/SourBugs)
For Names and Avatars:
In the rich text editor:
%SourBugs
In a comment:
[![SourBugs's Avatar](https://chowlings.com/images/avatars/default.jpg)](https://chowlings.com/user/SourBugs) [SourBugs](https://chowlings.com/user/SourBugs)