fix: missing order instances for Int (#12181)

This PR adds two missing order instances for `Int`.

As reported on
[Zulip](https://leanprover.zulipchat.com/#narrow/channel/270676-lean4/topic/No.20Std.2EMaxOrEq.20Int.20instance.2C.20but.20yes.20Std.2EMinOrEq.20Int/near/570198709).

src/Init/Data/Int/Order.lean

@@ -1447,4 +1447,12 @@ instance : LawfulOrderLT Int where
   lt_iff := by
     simp [← Int.not_le, Decidable.imp_iff_not_or, Std.Total.total]
 
+instance : LawfulOrderLeftLeaningMin Int where
+  min_eq_left _ _ := Int.min_eq_left
+  min_eq_right _ _ h := Int.min_eq_right (le_of_lt (not_le.1 h))
+
+instance : LawfulOrderLeftLeaningMax Int where
+  max_eq_left _ _ := Int.max_eq_left
+  max_eq_right _ _ h := Int.max_eq_right (le_of_lt (not_le.1 h))
+
 end Int