Disable certain characters in usernames

[Abronsyth]

Resolved

Hello!

So despite the very obvious warning I put on my registration page I still have users registering with special characters in their usernames, which makes it so that their profiles become unviewable and makes for some issues.

Is there a way to disable it so that if they attempt to register with a special character in the username it won't register them, but instead gives the warning "Sorry, please only use letters, numbers, or spaces in your username."