• change_tick_coords has never been used by any other function or in any
  example in the library's history, and is a custom API not even present
  on other AxisArtistHelpers, so deprecate it.
• _limits_inverted is only used in get_tick_iterators, so one can just
  test limits inversion there instead of carrying one bit of state
  around.

PR Summary

PR Checklist

• Has pytest style unit tests (andpytest passes).
• IsFlake 8 compliant (runflake8 on changed files to check).
• New features are documented, with examples if plot related.
• Documentation is sphinx and numpydoc compliant (the docs shouldbuild without error).
• Conforms to Matplotlib style conventions (installflake8-docstrings and runflake8 --docstring-convention=all).
• 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).