Log Message:
-----------
<optional> cannot be used here, because psql doesn't handle it.
Modified Files:
--------------
pgsql/doc/src/sgml/ref:
cluster.sgml (r1.43 -> r1.44)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/cluster.sgml?r1=1.43&r2=1.44)