"group privacy" -> "true group"

Co-authored-by: Dave Longley <[email protected]>

index.html

@@ -1413,9 +1413,9 @@ <h3>Decoy Values</h3>
       <p>
 When indexes of status list entries are allocated in a random fashion, which is
 the suggested mode of operation for this specification, adding decoys harms
-privacy because it reduces the group privacy size by the number of decoys added
+privacy because it reduces the true group size by the number of decoys added
 to the group. A random allocation of indexes inherently hides the true size of
-the group, ensuring that decoys are not necessary.
+the group without reducing it, ensuring that decoys are not necessary.
       </p>
       <p>
 There might be use cases where decoy values provide benefits. Implementers are