In the rich text editor:
@Lem0ns
In a comment:
[Lem0ns](https://chowlings.com/user/Lem0ns)
For Names and Avatars:
In the rich text editor:
%Lem0ns
In a comment:
[![Lem0ns's Avatar](https://chowlings.com/images/avatars/default.jpg)](https://chowlings.com/user/Lem0ns) [Lem0ns](https://chowlings.com/user/Lem0ns)