Fix issue where double decorator does not parse function name

[cvanelteren]

Context is in #319

[codecov]

Codecov Report

❌ Patch coverage is 91.66667% with 1 line in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
ultraplot/tests/test_inputs.py	85.71%	1 Missing ⚠️

📢 Thoughts on this report? Let us know!

[cvanelteren]

Needs a test

[cvanelteren]

Not sure why the test if failing on a non-related part.

[pgf]

If this fix the issue, the _preprocess_or_redirect decorator should be redundant also in the other tri* methods, tricontour(f), right?

[cvanelteren]

Yes!