DOCS: Enable numpydoc validation pre-commit hook

[tkknight]

🚀 Pull Request

Description

This pull-request enables the numpydoc pre-commit hook, which performs validation checks of all python docstrings to ensure that they comply with the numpydoc validation rules.

The check excludes:

• lib/iris/tests/
• docs/gallery_code/

The section [tool.numpydoc_validation] in pyproject.toml section defines all the rules to apply - which default to all with specific ignores that can be addressed over time.

This PR is based upon the GeoVista implementation https://github.com/bjlittle/geovista/pull/716.

A new issue will be created to track the outstanding rules to address.

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Consult Iris pull request check list

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 89.74%. Comparing base (8998779) to head (d130b51). Report is 4 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #5762   +/-   ##
=======================================
  Coverage   89.74%   89.74%           
=======================================
  Files          92       92           
  Lines       22940    22940           
  Branches     5462     5462           
=======================================
  Hits        20588    20588           
  Misses       1620     1620           
  Partials      732      732           

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[CLAassistant]

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