pgsql: Make the CREATE RULE syntax description in rules.sgml more

Log Message:
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Make the CREATE RULE syntax description in rules.sgml more consistent
with the syntax description in the CREATE RULE reference page. From
Kris Jurka.

Modified Files:
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pgsql/doc/src/sgml:
rules.sgml (r1.41 -> r1.42)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/rules.sgml.diff?r1=1.41&r2=1.42)