pgsql: Add table creation and population to example from John Gage

Log Message:
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Add table creation and population to example

from John Gage

Tags:
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REL9_0_STABLE

Modified Files:
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pgsql/doc/src/sgml:
xfunc.sgml (r1.149.2.1 -> r1.149.2.2)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/xfunc.sgml?r1=1.149.2.1&r2=1.149.2.2)