[CSS22] Better wording for change s.9.9.1.

Author: bert-github

css2/changes.src

@@ -911,10 +911,10 @@ term
 
    <li id=s.9.9.1 class=change>
     <p><span class=updated>[2015-07-01]</span> An element with
-    'position: fixed', unlike one with 'position: absolute',
+    'position: fixed'
     <em>always</em> establishes a new stacking context. (This is
     different from 'position: absolute', where 'z-index' determines if
-    the element establishes a stacking context.)
+    the element establishes a stacking context or not.)
 
     <p>Change the definition of 'auto' in <a
     href="visuren.html#z-index" >&ldquo;9.9.1 Specifying the stack