pgsql: docs: add backend_type to file-fdw CSV log example

docs: add backend_type to file-fdw CSV log example

backend_type was added to the CVS log output in commit 70a7b4776b.

Reported-by: Fabrízio de Royes Mello

Discussion: /messages/by-id/CAFcNs+ruvRks3BV1j7yQ-MvxsswmKJa0cVh2yK5Dd-xXVM8wPw@mail.gmail.com

Backpatch-through: master

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/0830d21f5b01064837dc8bd910ab31a5b7a1101a

Modified Files
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doc/src/sgml/file-fdw.sgml | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)