doc: Fix link to pg_ident_file_mappings view

Commit a2c8499 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

Author: danielgustafsson

doc/src/sgml/func.sgml

@@ -26340,7 +26340,7 @@ SELECT collation for ('foo' COLLATE "de_DE");
         of its children.) You can use the
         <link linkend="view-pg-file-settings"><structname>pg_file_settings</structname></link>,
         <link linkend="view-pg-hba-file-rules"><structname>pg_hba_file_rules</structname></link> and
-        <link linkend="view-pg-hba-file-rules"><structname>pg_ident_file_mappings</structname></link> views
+        <link linkend="view-pg-ident-file-mappings"><structname>pg_ident_file_mappings</structname></link> views
         to check the configuration files for possible errors, before reloading.
        </para></entry>
       </row>