Fix flake8 lint in geometric_features

[xylar]

This merge addresses all the lint identified by flake8 within the geometric_features package. Notably, it doesn't address the feature_creation_scripts directory, which is there for provenance and we don't necessarily try to keep it clean or up-to-date.

[xylar]

@altheaden, it seems like flake8 and maybe the other pre-commit features are running on all files in CI and not just the modified files. Can you figure out how to change that? Feel free to push changes here.

[xylar]

@altheaden, as I just slacked you, I got it.