undo-files: clean existing files up before writing new one
the in the initial design of journal/undo interaction, ages ago, new file always
overwrote previous files. This is no longer the case for a long while, so it is
time to properly clean things up before writing new ones.
Otherwise, inconsistent "undo" state might exist on disk, leading `hg rollback`
to misbehave (more that intended).
[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