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