Fix link to MathML section (#12242)

Author: dontcallmedom

css-text-4/Overview.bs

@@ -793,7 +793,7 @@ Case Transforms: the 'text-transform' property</h3>
 
 		<dt><dfn>math-auto</dfn>
 		<dd>
-			See [[mathml-core#new-text-transform-values]].
+			See [[mathml-core#math-auto-transform]].
 
 			<wpt>
 			text-transform/math/text-transform-math-auto-001.html