postgres_fdw: use_scram_passthrough on user mapping is ignored when also set on server

Hi,

use_scram_passthrough can be specified both on a foreign server and
on a user mapping. I found that when both are specified, currently
the server-level setting overrides the user mapping setting. Is this
precedence intentional?

That seems inconsistent with the usual expectation that foreign server
options act as shared defaults, while user mapping options provide
per-user overrides. If the same option is specified in both places,
I would expect the user mapping setting to take precedence. Thoughts?

If the current behavior is intentional, I'd like to document the precedence
when use_scram_passthrough is specified in both a foreign server and
a user mapping. Otherwise, I'd like to change postgres_fdw to prefer
the user mapping setting and update the documentation accordingly.

Regards,

--
Fujii Masao