How to suppress CSS comment syntax error?

[erosman]

Is there a way to suppress the following syntax error?
(I was able to suppress the error in CodeMirror )

Setting language to SCSS and using // .... didn’t help.
All suggestions are welcomed.

/*
==UserCSS==
@name           Github
@match          https://github.com/*/issues*
@version        1.0
==/UserCSS==
*/

body {
  border: 1px solid red;
}

PS. How do you change the language on playground?