copies-rust: record "overwritten" information from both side on delete
With this change, we can ensure every (`dest`, `rev`) points to the same value,
making a lots of comparison simpler.
Differential Revision: https://phab.mercurial-scm.org/D9652
[tool.black]
line-length = 80
exclude = '''
build/
| wheelhouse/
| dist/
| packages/
| \.hg/
| \.mypy_cache/
| \.venv/
| mercurial/thirdparty/
'''
skip-string-normalization = true
quiet = true