Prettify autogeneration of classifiers.py

[cthoyt]

Suggested in #34 (comment)

Alternatively, the code could be upgraded to

out.write(b'''LICENSE_CODES = {\n''')
for license, codes in license_map.items():
    out.write(b'    "%s": {\n' % license)
    for code in codes:
        out.write(b'        "%s",\n' % code)
    out.write(b'    },\n')
out.write(b'''}\n\n''')

out.write(b'''CODE_LICENSES = {\n''')
for code, licenses in code_map.items():
    out.write(b'    "%s": {\n' % code)
    for license in licenses:
        out.write(b'        "%s",\n' % license)
    out.write(b'    },\n')
out.write(b'''}\n\n''')

to much better address formatting, and uses lots of trailing commas to make diffs smaller!

[regebro]

Thanks! I've done this (or at least something similar) as a part of reformatting all the code with black. This file will not be entirely black compatible, because that depends on how long each line is, but stil...