We don't remove zero-count patches, as can easily be checked with e.g.
print(hist([0, 0, 0, 10], 10, log=True)). The incorrect statement
came in in f24d06c, but it is clear that that patch did not implement
that behavior, instead filtering out such patches in
_update_patch_limits.

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).