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