PR Summary

I'm guessing 99.9% of the use of gridspec_kws is to set the height or width ratios of axes. And it is pretty esoteric to ask people to know about gridspecs in order to access this. Here we addwidth_ratios andheight_ratios to the subplots and subplot_mosaic calls.

Previously we would do

fig,axs=plt.subplots(1,2,gridspec_kw={'width_ratios': [1,2]})

This PR allows

fig,axs=plt.subplots(1,2,width_ratios=[1,2])

PR Checklist

Tests and Styling

• Has pytest style unit tests (andpytest passes).
• IsFlake 8 compliant (installflake8-docstrings and runflake8 --docstring-convention=all).

Documentation

• New features are documented, with examples if plot related.
• New features have an entry indoc/users/next_whats_new/ (follow instructions in README.rst there).
• API changes documented indoc/api/next_api_changes/ (follow instructions in README.rst there).
• Documentation is sphinx and numpydoc compliant (the docs shouldbuild without error).