pgsql: Add URL for: * Implement SQL:2003 window functions >

Log Message:
-----------
Add URL for:

* Implement SQL:2003 window functions

http://archives.postgresql.org/pgsql-hackers/2008-07/msg00232.php

Modified Files:
--------------
pgsql/doc:
TODO (r1.2491 -> r1.2492)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/TODO?r1=1.2491&r2=1.2492)
pgsql/doc/src/FAQ:
TODO.html (r1.997 -> r1.998)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/src/FAQ/TODO.html?r1=1.997&r2=1.998)