Enable ruff formatting of docstrings

[drbenvincent]

• Updates pyproject.toml to get ruff to format docstrings. Triggered in pre-commit checks.
• Ran that, so we've got formatting updates to a bunch of docstrings.

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📚 Documentation preview 📚: https://causalpy--430.org.readthedocs.build/en/430/

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 94.40%. Comparing base (e61bfd0) to head (796cb26).
Report is 5 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #430   +/-   ##
=======================================
  Coverage   94.40%   94.40%           
=======================================
  Files          31       31           
  Lines        1985     1985           
=======================================
  Hits         1874     1874           
  Misses        111      111           

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