Fix broken-FK-detection query in release notes

Commits 53af9491a0 and 2d5fe51405 fixed a number of problems with
foreign keys that reference partitioned tables, and a query to detect
already broken FKs was supplied with the release notes for 17.1, 16.5,
15.9, 14.14, 13.17.  However, that query has a bug that causes it to
wrongly report self-referential foreign keys even when they are correct,
so if the user was to drop and rebuild the FKs as indicated, the query
would continue to report them as needing to be repaired.  Here we fix
the query to not have that problem.

Reported-by: Paul Foerster <paul.foerster@gmail.com>
Discussion: https://postgr.es/m/5456A1D0-CD47-4315-9C65-71B27E7A2906@gmail.com
Backpatch-through: 13-17

doc/src/sgml/release-14.sgml

@@ -2674,10 +2674,14 @@ FROM pg_catalog.pg_constraint c
 WHERE contype = 'f' AND conparentid = 0 AND
    (SELECT count(*) FROM pg_catalog.pg_constraint c2
     WHERE c2.conparentid = c.oid) <>
-   (SELECT count(*) FROM pg_catalog.pg_inherits i
+   ((SELECT count(*) FROM pg_catalog.pg_inherits i
     WHERE (i.inhparent = c.conrelid OR i.inhparent = c.confrelid) AND
       EXISTS (SELECT 1 FROM pg_catalog.pg_partitioned_table
-              WHERE partrelid = i.inhparent));
+              WHERE partrelid = i.inhparent)) +
+    CASE WHEN pg_catalog.pg_partition_root(conrelid) = confrelid THEN
+              (SELECT count(*) FROM pg_catalog.pg_partition_tree(confrelid)
+                WHERE level = 1)
+         ELSE 0 END);
 </programlisting>
       Since it is possible that one or more of the <literal>ADD
       CONSTRAINT</literal> steps will fail, you should save the query's