pgsql: Fix documentation example of using psql \x with a SELECT command,

Log Message:
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Fix documentation example of using psql \x with a SELECT command, per
Simon Riggs. Backpatch to 8.2.X.

Tags:
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REL8_2_STABLE

Modified Files:
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pgsql/doc/src/sgml/ref:
psql-ref.sgml (r1.175 -> r1.175.2.1)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/psql-ref.sgml.diff?r1=1.175&r2=1.175.2.1)