[selectors-4][editorial] Remove ancient note about :visited and :active

Author: tabatkins

selectors-4/Overview.bs

@@ -2246,8 +2246,6 @@ The Activation Pseudo-class: '':active''</h3>
 	(including non-element nodes, such as text nodes)
 	matches the above conditions.
 
-	Note: An element can be both '':visited'' and '':active''
-	(or '':link'' and '':active'').
 
 <h3 id="the-focus-pseudo">
 The Input Focus Pseudo-class: '':focus''</h3>