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