[css-syntax][meta] Whoops, remove final lingering incorrect normative ref.

Author: tabatkins

css-syntax-3/Overview.bs

@@ -3182,7 +3182,7 @@ Style rules</h3>
 	that associates a <a>selector list</a>
 	with a list of property declarations.
 	They are also called
-	<a href="https://www.w3.org/TR/CSS2/syndata.html#rule-sets">rule sets</a> in [[!CSS2]].
+	<a href="https://www.w3.org/TR/CSS2/syndata.html#rule-sets">rule sets</a> in [[CSS2]].
 	CSS Cascading and Inheritance [[CSS-CASCADE-3]] defines how the declarations inside of style rules participate in the cascade.
 
 	The prelude of the qualified rule is [=CSS/parsed=]