Fix comment in pg_db_role_setting.h

Noted by Japin Li

Discussion: https://www.postgresql.org/message-id/MEYP282MB16691ACEDBC94161CF4BA1CCB69A9%40MEYP282MB1669.AUSP282.PROD.OUTLOOK.COM

Author: j-naylor

src/include/catalog/pg_db_role_setting.h

@@ -51,7 +51,7 @@ DECLARE_TOAST_WITH_MACRO(pg_db_role_setting, 2966, 2967, PgDbRoleSettingToastTab
 DECLARE_UNIQUE_INDEX_PKEY(pg_db_role_setting_databaseid_rol_index, 2965, DbRoleSettingDatidRolidIndexId, on pg_db_role_setting using btree(setdatabase oid_ops, setrole oid_ops));
 
 /*
- * prototypes for functions in pg_db_role_setting.h
+ * prototypes for functions in pg_db_role_setting.c
  */
 extern void AlterSetting(Oid databaseid, Oid roleid, VariableSetStmt *setstmt);
 extern void DropSetting(Oid databaseid, Oid roleid);