doc: clarify logical decoding's deadlock of system tables

Reported-by: andyatkinson@gmail.com

Discussion: https://postgr.es/m/166631875298.630.2861049399528658047@wrigleys.postgresql.org

Backpatch-through: master

doc/src/sgml/logicaldecoding.sgml

@@ -1197,9 +1197,8 @@ OutputPluginWrite(ctx, true);
       </listitem>
      </itemizedlist>
 
-     Note that these commands that can cause deadlock apply to not only explicitly
-     indicated system catalog tables above but also to any other [user] catalog
-     table.
+     Note that these commands can cause deadlocks not only for the system
+     catalog tables listed above but for other catalog tables.
     </para>
    </sect2>
   </sect1>