TYP: remove #type:ignore from core.arrays.datetimelike
pandas\core\arrays\datetimelike.py:1535: error: Signatures of "__iadd__" and "__add__" are incompatible
pandas\core\arrays\datetimelike.py:1544: error: Signatures of "__isub__" and "__sub__" are incompatible
Nice, LGTM pending green Thanks @simonjayhawkins 