add link to CPython issue in comment for future reference
add link to CPython issue in comment for future reference

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