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