remove extras require dead code that never worked in the first place

Signed-off-by: Stephen L. <lrq3000@gmail.com>

pyproject.toml

@@ -62,7 +62,7 @@ Download = "https://github.com/tomerfiliba/reedsolomon/releases"
 #Changelog = "https://url/changelog"
 
 #[project.optional-dependencies]
-#cythonize = [
+#cythonize = [  # cython and other build time dependencies can NOT be defined as optional-dependencies nor extras, they are installed only after build! They need to be defined as build-system requirements
 #    "cython>=3.0.0b2"
 #]
 

setup.py

@@ -69,9 +69,6 @@
         },  # see: https://stackoverflow.com/questions/61156290/how-to-set-project-links-in-pypi and https://github.com/pypi/warehouse/blob/main/warehouse/templates/packaging/detail.html
     py_modules = ["reedsolo"],
     platforms = ["any"],
-    #extras_require={
-        #"cythonize": ["cython>=3.0.0b2"],  # see: https://hynek.me/articles/python-recursive-optional-dependencies/ and https://copyprogramming.com/howto/optional-dependencies-in-a-pip-requirements-file
-        #},
     long_description = open("README.rst", "r").read(),
     long_description_content_type = 'text/x-rst',
     license_files = ('LICENSE',),  # force include LICENSE file, requires setuptools >= 42.0.0. Note that this field only support one line text, do not input the full license content here. The full LICENSE file is currently forcefully included via MANIFEST.in, but other methods exist, see: https://stackoverflow.com/a/66443941/1121352