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