Remove outdated whitespace checks from patchcheck list

[hugovk]

The whitespace checks are now part of pre-commit and not patchcheck:

❯ make patchcheck
...
Checked 114 modules (35 built-in, 79 shared, 0 n/a on macosx-15.5-arm64, 0 disabled, 0 missing, 0 failed on import)
./python.exe -E ./Tools/build/generate-build-details.py `cat pybuilddir.txt`/build-details.json
./python.exe ./Tools/patchcheck/patchcheck.py
Getting base branch for PR ... upstream/main
Getting the list of files that have been added/changed ... 13 files
Docs modified ... yes
Misc/ACKS updated ... NO
Misc/NEWS.d updated with `blurb` ... yes
configure regenerated ... not needed
pyconfig.h.in regenerated ... not needed

Did you run the test suite and check for refleaks?

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📚 Documentation preview 📚: https://cpython-devguide--1592.org.readthedocs.build/

[StanFromIreland]

LGTM