Add __divmod__ to numeric types (#1900)

Helps with #1889

stdlib/2and3/fractions.pyi

@@ -62,6 +62,8 @@ class Fraction(Rational):
     def __rfloordiv__(self, other) -> int: ...
     def __mod__(self, other): ...
     def __rmod__(self, other): ...
+    def __divmod__(self, other): ...
+    def __rdivmod__(self, other): ...
     def __pow__(self, other): ...
     def __rpow__(self, other): ...