Update obsolete text in fdwhandler.sgml.
Update obsolete text in fdwhandler.sgml.

Etsuro Fujita, with some wording adjustment by me.

postmind-net/postgres-xl,arcivanov/postgres-xl,kmjungersen/PostgresXL,postmind-net/postgres-xl,arcivanov/postgres-xl,postmind-net/postgres-xl,arcivanov/postgres-xl,kmjungersen/PostgresXL,postmind-net/postgres-xl,snaga/postgres-xl,kmjungersen/PostgresXL,snaga/postgres-xl,arcivanov/postgres-xl,kmjungersen/PostgresXL,arcivanov/postgres-xl,snaga/postgres-xl,arcivanov/postgres-xl,postmind-net/postgres-xl,snaga/postgres-xl,kmjungersen/PostgresXL,snaga/postgres-xl