update boundary mode in profile_line

[grlee77]

Description

This PR resolves a TODO item related to switching the default profile_line boundary mode to 'reflect' for release 0.19. I also added a small change to fix the behavior for modes 'constant' and 'wrap' using their new implementations from SciPy 1.6 when available. This fixes, for example, the unexpected behavior raised at the top of gh-4279.

Checklist

• Docstrings for all functions
• Gallery example in ./doc/examples (new features only)
• Benchmark in ./benchmarks, if your changes aren't covered by an
  existing benchmark
• Unit tests
• Clean style in the spirit of PEP8

For reviewers

• Check that the PR title is short, concise, and will make sense 1 year
  later.
• Check that new functions are imported in corresponding __init__.py.
• Check that new features, API changes, and deprecations are mentioned in
  doc/release/release_dev.rst.

[jni]

❤️

[rfezzani]

Thank you @grlee77, it seems that we need a rebase before merging 😉

[pep8speaks]

Hello @grlee77! Thanks for updating this PR. We checked the lines you've touched for PEP 8 issues, and found:

There are currently no PEP 8 issues detected in this Pull Request. Cheers! 🍻

Comment last updated at 2021-01-22 12:35:35 UTC

[rfezzani]

Thank you @grlee77 🎉