hash-keys: support try-order argument

Author: cloudrac3r

typed-racket-lib/typed-racket/base-env/base-env.rkt

@@ -1048,7 +1048,9 @@
 [hash-count (-> -HashTableTop -Index)]
 [hash-empty? (-> -HashTableTop -Boolean)]
 [hash-keys (-poly (a b) (cl-> [((-HT a b)) (-lst a)]
-                              [(-HashTableTop) (-lst Univ)]))]
+                              [((-HT a b) -Boolean) (-lst a)]
+                              [(-HashTableTop) (-lst Univ)]
+                              [(-HashTableTop -Boolean) (-lst Univ)]))]
 [hash-values (-poly (a b) (cl-> [((-HT a b)) (-lst b)]
                                 [(-HashTableTop) (-lst Univ)]))]
 [hash->list (-poly (a b) (cl-> [((-HT a b)) (-lst (-pair a b))]