pgsql: Add URLs for: * Add REPLACE or UPSERT command that does UPDATE,

Log Message:
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Add URLs for:

* Add REPLACE or UPSERT command that does UPDATE, or on failure, INSERT
[merge]

Modified Files:
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pgsql/doc:
TODO (r1.2116 -> r1.2117)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/TODO.diff?r1=1.2116&r2=1.2117)
pgsql/doc/src/FAQ:
TODO.html (r1.617 -> r1.618)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/FAQ/TODO.html.diff?r1=1.617&r2=1.618)