pgsql: doc: Fix link to pg_ident_file_mappings view

doc: Fix link to pg_ident_file_mappings view

Commit a2c84990bea7 accidentally used the link for pg_hba_file_rules
when linking to pg_ident_file_mappings.  Backpatch to v16 where this
was introduced.

Author: Erik Wienhold <ewie@ewie.name>
Discussion: https://postgr.es/m/qt5hvgvfi4qzlgml2dfssaut2t2x5nwf7b5l63fklr7fpxwm6g@hle3mtglpm4y
Backpatch-through: v16

Branch
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REL_16_STABLE

Details
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https://git.postgresql.org/pg/commitdiff/21d521ded33fdc9901cba7e8ecb3e03003007845

Modified Files
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doc/src/sgml/func.sgml | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)