doc: mention that ANALYZE does block DDL

Reported-by: Aramaki Zyake

Discussion: https://postgr.es/m/156628723253.1296.7377373462603881976%40wrigleys.postgresql.org

Author: Aramaki Zyake

Backpatch-through: master

Author: bmomjian

doc/src/sgml/ref/analyze.sgml

@@ -208,7 +208,7 @@ ANALYZE [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] [ <r
   <para>
    <command>ANALYZE</command>
    requires only a read lock on the target table, so it can run in
-   parallel with other activity on the table.
+   parallel with other non-DDL activity on the table.
   </para>
 
   <para>