patch: add hint about mangled whitespace on bad patch
One of the most common reasons that a patch doesn't apply is because
its whitespace has been mangled (e.g. by their mail client or though
copy&paste). Let's provide a hint about that.
Differential Revision: https://phab.mercurial-scm.org/D11825
[build-system]
requires = ["setuptools", "wheel"]
[tool.black]
line-length = 80
exclude = '''
build/
| wheelhouse/
| dist/
| packages/
| \.hg/
| \.mypy_cache/
| \.venv/
| mercurial/thirdparty/
'''
skip-string-normalization = true
quiet = true