relnotes: GND is not -XSafe compatible.

Signed-off-by: Austin Seipp <austin@well-typed.com>
(cherry picked from commit 73cab206)

docs/users_guide/7.8.1-notes.xml

@@ -108,11 +108,6 @@
 
                 For more information, see <xref linkend="roles"/>.
           </para>
-           <para>
-                As a result of this change,
-                <literal>GeneralizedNewtypeDeriving</literal> can now
-                be used with Safe Haskell.
-          </para>
        </listitem>
 
         <listitem>