[css-pseudo-4][editorial] Improve wording for clarity

Author: fantasai

css-pseudo-4/Overview.bs

@@ -920,7 +920,7 @@ List Markers: the ''::marker'' pseudo-element</h3>
   of ''::before'' or ''::after'' pseudo-elements that happen to be [=list items=].
   However ''::marker::marker'' is invalid,
   and the computed value of 'display' on ''::marker''
-  loses its ''display/list-item'' aspect.
+  always loses any ''display/list-item'' aspect.
 
 <h3 id="placeholder-pseudo">
 Placeholder Input: the ''::placeholder'' pseudo-element</h3>