PR Summary

As per #11434 its a bit of a pain to get the gridspec after calling plt.subplots(). This change lets you do the following, where the only really change is that we don't have to do the more cumbersome gs = ax.get_suplotspec().get_gridspec(). Much more discoverable.

To do: Add to gridspec tutorial which I'll d if this is in general OK. I don't see the harm in adding this.

    import matplotlib.pyplot as plt

    fig, axs = plt.subplots(3, 2)
    gs = axs[0, -1].get_gridspec()

    # remove the last column
    for ax in axs[:,-1].flatten():
      ax.remove()

    # make a subplot in last column that spans rows.
    ax = fig.add_subplot(gs[:, -1])
    plt.show()

PR Checklist

• Has Pytest style unit tests
• Code is PEP 8 compliant
• New features are documented, with examples if plot related
• Documentation is sphinx and numpydoc compliant
• Added an entry to doc/users/next_whats_new/ if major new feature (follow instructions in README.rst there)