decompressoriterator: convert Py_DecRef to Py_XDECREF
decompressoriterator: convert Py_DecRef to Py_XDECREF

They are equivalent. The macro is preferred.
indygreg/python-zstandard,indygreg/python-zstandard,terrelln/python-zstandard,terrelln/python-zstandard,terrelln/python-zstandard,indygreg/python-zstandard,terrelln/python-zstandard,indygreg/python-zstandard