Update create_rule manual page.

doc/src/sgml/func.sgml

doc/src/sgml/ref/create_rule.sgml

src/backend/utils/adt/formatting.c

src/test/regress/expected/int8.out

src/test/regress/expected/numeric.out

src/test/regress/expected/timestamp.out

src/test/regress/sql/int8.sql

src/test/regress/sql/numeric.sql

src/test/regress/sql/timestamp.sql