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