largefiles: replace use of walkchangerevs() with simple revset query
Since it does nothing in prepare(), what we're doing is just walking
revisions matching ".hglf" in reverse order.
[tool.black]
line-length = 80
exclude = '''
build/
| wheelhouse/
| dist/
| packages/
| \.hg/
| \.mypy_cache/
| \.venv/
| mercurial/thirdparty/
'''
skip-string-normalization = true
quiet = true