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