Improve GRANT reference page's description of object ownership

privileges by mentioning the possibility of granting membership in
the owning role.

doc/src/sgml/ref/grant.sgml

@@ -1,5 +1,5 @@
 <!--
-$PostgreSQL: pgsql/doc/src/sgml/ref/grant.sgml,v 1.74 2009/01/22 20:15:59 tgl Exp $
+$PostgreSQL: pgsql/doc/src/sgml/ref/grant.sgml,v 1.75 2009/09/12 16:26:06 tgl Exp $
 PostgreSQL documentation
 -->
 
@@ -121,9 +121,14 @@ GRANT <replaceable class="PARAMETER">role</replaceable> [, ...] TO <replaceable
    (usually the user that created it),
    as the owner has all privileges by default.  (The owner could,
    however, choose to revoke some of his own privileges for safety.)
-   The right to drop an object, or to alter its definition in any way is
-   not described by a grantable privilege; it is inherent in the owner,
-   and cannot be granted or revoked.  The owner implicitly has all grant
+  </para>
+
+  <para>
+   The right to drop an object, or to alter its definition in any way, is
+   not treated as a grantable privilege; it is inherent in the owner,
+   and cannot be granted or revoked.  (However, a similar effect can be
+   obtained by granting or revoking membership in the role that owns
+   the object; see below.)  The owner implicitly has all grant
    options for the object, too.
   </para>