Add support for first, last aggregate function parsing (#882)

* Add order by parsing to functions

* Fix doc error

* minor changes

tests/sqlparser_hive.rs

@@ -346,6 +346,7 @@ fn parse_delimited_identifiers() {
             over: None,
             distinct: false,
             special: false,
+            order_by: vec![],
         }),
         expr_from_projection(&select.projection[1]),
     );