doc: Clarify pg_inherits description

Reported-by: mjustin.lists@gmail.com

doc/src/sgml/catalogs.sgml

@@ -3848,7 +3848,7 @@ SCRAM-SHA-256$<replaceable>&lt;iteration count&gt;</>:<replaceable>&lt;salt&gt;<
   <para>
    The catalog <structname>pg_inherits</> records information about
    table inheritance hierarchies.  There is one entry for each direct
-   child table in the database.  (Indirect inheritance can be determined
+   parent-child table relationship in the database.  (Indirect inheritance can be determined
    by following chains of entries.)
   </para>