Log Message:
-----------
Mention related ALTER TABLE variants in documentation for CLUSTER.
As suggested by Andy Lester.
Modified Files:
--------------
pgsql/doc/src/sgml/ref:
cluster.sgml (r1.49 -> r1.50)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/cluster.sgml?r1=1.49&r2=1.50)