Add mypy test capability to PureDoctestTestCase
Add mypy test capability to PureDoctestTestCase

* run mypy against test modules tagged with `mypy`

cython/cython,da-woods/cython,scoder/cython,da-woods/cython,da-woods/cython,cython/cython,scoder/cython,scoder/cython,cython/cython,scoder/cython,cython/cython,da-woods/cython