[css-lists-3] Remove the now somewhat-confusing 'counter name' dfn.

Author: tabatkins

css-lists-3/Overview.bs

@@ -700,7 +700,7 @@ Creating Counters: the 'counter-reset' property</h3>
 
 		<dt><dfn><<counter-name>> <<integer>>?</dfn>
 		<dd>
-			[=Instantiates=] a counter of the given <<counter-name>> <dfn>counter name</dfn>
+			[=Instantiates=] a counter of the given <<counter-name>>
 			with a starting value of the given <<integer>>,
 			defaulting to ''0''.
 	</dl>