PR Summary

I think we should have more "Labelling" tutorials. The natural place for that is under "Text" which I propose here to rename "Labelling plots". I envision adding an Axis/ticker tutorial here, and an annotations tutorial, but for now, lets move "Legends" there.

(I also think we should consolidate some of the tutorials in this section... I don't think Luatex needs a dfferent tutorial from usetex)

PR Checklist

Tests and Styling

• Has pytest style unit tests (and pytest passes).
• Is Flake 8 compliant (install flake8-docstrings and run flake8 --docstring-convention=all).

Documentation

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