We don't need to separately track (and maintain refcounts) for
PyFT2Font.fname; we can simply infer it from py_file (the file object)
as needed. Note that if FT2Font was directly constructed with a
file-like arg, the fname attribute (both previously and with this PR) is
the file-like, not its name.

PR Summary

PR Checklist

• Has pytest style unit tests (and pytest passes).
• Is Flake 8 compliant (run flake8 on changed files to check).
• New features are documented, with examples if plot related.
• Documentation is sphinx and numpydoc compliant (the docs should build without error).
• Conforms to Matplotlib style conventions (install flake8-docstrings and run flake8 --docstring-convention=all).
• New features have an entry in doc/users/next_whats_new/ (follow instructions in README.rst there).
• API changes documented in doc/api/next_api_changes/ (follow instructions in README.rst there).