pgsql: Make pg_restore usage examples more useful: illustrate restoring

Log Message:
-----------
Make pg_restore usage examples more useful: illustrate restoring into
both the same database name and a different one.

Modified Files:
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pgsql/doc/src/sgml/ref:
pg_restore.sgml (r1.63 -> r1.64)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/pg_restore.sgml.diff?r1=1.63&r2=1.64)