pgsql: doc: Clarify OAuth validator authn_id logging

doc: Clarify OAuth validator authn_id logging

Document that OAuth validators can return an authenticated identity
in the authn_id member. The server records the identity value before
checking if the connection is authorized, so it may appear in
connection-authentication logs (even if the connection later fails
authorization).

Also remove outdated wording saying that all result parameters are
ignored when a validator returns false since validators may provide
error_detail.

Patch by Chao Li with some additional wordsmithing by me.

Author: Chao Li <lic(at)highgo(dot)com>
Reviewed-by: Jacob Champion <jacob(dot)champion(at)enterprisedb(dot)com>
Reported-by: Daniel Gustafsson <daniel(at)yesql(dot)se>
Discussion: https://postgr.es/m/0281836A-F5FF-41A5-9EE1-656C1FAAC6B2@gmail.com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/4cb2e2fe0aa8251bef8c2e2351cd5a062c105c0a

Modified Files
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doc/src/sgml/oauth-validators.sgml | 13 +++++++++----
1 file changed, 9 insertions(+), 4 deletions(-)