Linting adjustments

[clmould]

Description

Checklist

I confirm that I have completed the following checks:

• My changes follow the PROCESS style guide
• I have justified any large differences in the regression tests caused by this pull request in the comments.
• I have added new tests where appropriate for the changes I have made.
• If I have had to change any existing unit or integration tests, I have justified this change in the pull request comments.
• If I have made documentation changes, I have checked they render correctly.
• I have added documentation for my change, if appropriate.

[codecov-commenter]

Codecov Report

❌ Patch coverage is 38.42975% with 149 lines in your changes missing coverage. Please review.
✅ Project coverage is 46.29%. Comparing base (ee78ba0) to head (c442b1f).

Files with missing lines	Patch %	Lines
process/io/mfile2dict.py	62.35%	32 Missing ⚠️
process/pfcoil.py	0.00%	20 Missing ⚠️
process/stellarator.py	0.00%	15 Missing ⚠️
process/io/plot_proc.py	13.33%	13 Missing ⚠️
process/io/plot_scans.py	0.00%	9 Missing ⚠️
process/blanket_library.py	16.66%	5 Missing ⚠️
process/costs_2015.py	28.57%	5 Missing ⚠️
process/geometry/shield_geometry.py	0.00%	4 Missing ⚠️
process/io/plot_stress_tf.py	0.00%	4 Missing ⚠️
process/physics.py	0.00%	4 Missing ⚠️
... and 25 more

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4016      +/-   ##
==========================================
+ Coverage   46.25%   46.29%   +0.03%     
==========================================
  Files         123      123              
  Lines       28861    28841      -20     
==========================================
+ Hits        13350    13351       +1     
+ Misses      15511    15490      -21     

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[je-cook]

Now #3983 is in this can tackle the second follow on point of

• Enable more ruff rules and fix any issues

Originally posted by @timothy-nunn in #3983 (comment)