PR Summary

Since 958e329 the preferred keyword for controlling the number of columns in a legend is ncols. However,

$git grep ncol= a30c0b13386ca9469ffcfed5fa24fd21aaba49c5  # current main

reveals several uses of the old keyword. This pull request replaces most of them with the new recommended ncols, but three uses of ncol should remain in place:

• an old what's new entry:

  matplotlib/doc/users/prev_whats_new/whats_new_0.98.4.rst

  Line 40 in a30c0b1

  leg = plt.legend(loc='best', ncol=2, mode="expand", shadow=True, fancybox=True)

• the definition of the old keyword for backwards compatibility:

  matplotlib/lib/matplotlib/legend.py

  Line 383 in a30c0b1

  ncol=1, # synonym for ncols (backward compatibility)

• a test that checks that the old keyword still works:

  matplotlib/lib/matplotlib/tests/test_legend.py

  Line 1220 in a30c0b1

  fig_test.legend(strings, ncol=ncols)

PR Checklist

Documentation and Tests

• Has pytest style unit tests (and pytest passes)
• [N/A] Documentation is sphinx and numpydoc compliant (the docs should build without error).
• [N/A] New plotting related features are documented with examples.

Release Notes

• [N/A] New features are marked with a .. versionadded:: directive in the docstring and documented in doc/users/next_whats_new/
• [N/A] API changes are marked with a .. versionchanged:: directive in the docstring and documented in doc/api/next_api_changes/
• [N/A] Release notes conform with instructions in next_whats_new/README.rst or next_api_changes/README.rst