Geocat-comp ruff cleanup

[cyschneck]

PR Summary

Closes #583

PR Checklist

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[cyschneck]

Currently:

ruff check --per-file-ignores="__init__.py:F401" .

docs/conf.py:15:8: F401 [*] `os` imported but unused
docs/conf.py:25:1: E402 Module level import not at top of file
docs/conf.py:176:1: E402 Module level import not at top of file
geocat/comp/climatologies.py:1:8: F401 [*] `cf_xarray` imported but unused
geocat/comp/meteorology.py:115:9: F841 Local variable `eqtype` is assigned to but never used
Found 5 errors.

The os is not being used in conf.py, but there is reference to how it could be used if there was a need. Should it be removed?

The other two for conf.py are because the imports happen after the comment block, is it alright to move them above the template comment block?

climatologies.py does need cf_xarray (geocat/comp/climatologies.py:30: in _get_time_coordinate_info time = dset.cf["time"]) but it is called as cf instead of cf_xarray so ruff doesn't see how it is being used.

eqtype in the meteorology.py is a variable that is either set to 0 or 1 and then returned at the end for _xheat_index or not when it is used in the _heat_index, so it is technically never used in the _heat_index function on line 115

[anissa111]

We do actually need the cf_xarray imports. They aren't "used"/called directly, but provide an accessor to some xarray objects.

[kafitzgerald]

Looks good to me aside from the cf_xarray bit Anissa already caught!