Log Message:
-----------
Add link to major version release notes at the top of the minor
version ones, to make it clear to users just browsing the notes
that there are a lot more changes available from whatever version
they are at than what's in the minor version release notes.
Modified Files:
--------------
pgsql/doc/src/sgml:
release.sgml (r1.580 -> r1.581)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/release.sgml?r1=1.580&r2=1.581)