Update mypy config

[ffl096]

• show_error_codes is the default since a few mypy versions.
• Add stricter rules as suggested by scientific python: https://learn.scientific-python.org/development/guides/style/#MY104

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 97.36%. Comparing base (510eba3) to head (31de2fd).

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #374   +/-   ##
=======================================
  Coverage   97.36%   97.36%           
=======================================
  Files          38       38           
  Lines        3561     3561           
=======================================
  Hits         3467     3467           
  Misses         94       94           

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