Using "\n".join to keep things properly indented should have negligible
overhead compared to the subsequent tex subprocess invocation. Also,
generating TeX strings (with a lot of curly braces) is one of the few
cases where old-style (%) formatting is more legible than .format
formatting.

(The papersize option of geometry is documented as equivalent to
{paperwidth,paperheight}).

PR Summary

PR Checklist

• Has pytest style unit tests (and pytest passes).
• Is Flake 8 compliant (run flake8 on changed files to check).
• New features are documented, with examples if plot related.
• Documentation is sphinx and numpydoc compliant (the docs should build without error).
• Conforms to Matplotlib style conventions (install flake8-docstrings and run flake8 --docstring-convention=all).
• 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).