[selectors-4] :lang() with asterisks could be escaped also. Fixes w3c#3075

Author: fantasai

selectors-4/Overview.bs

@@ -1890,7 +1890,8 @@ The Language Pseudo-class: '':lang()''</h3>
 	argument. Each <dfn>language range</dfn> in '':lang()''
 	must be a valid CSS <<ident>> or <<string>>.
 	(Language ranges containing asterisks, for example,
-		must be quoted as strings.)
+		must be either correctly escaped or quoted as strings,
+		e.g. '':lang(\*-Latn)'' or '':lang("*-Latn")'')
 
 	Note: The <a>content language</a> of an element is defined by the document language.
 	For example, in HTML [[HTML5]], the <a>content language</a> is determined by a