psql: support `\d NAME` command: query #8

SELECT c.oid::pg_catalog.regclass
	FROM pg_catalog.pg_class c, pg_catalog.pg_inherits i
	WHERE c.oid = i.inhparent AND i.inhrelid = '1259'
	  AND c.relkind != 'p' AND c.relkind != 'I'
	ORDER BY inhseqno;