typing: add a few type hints to `mercurial/revlog.py`
Somewhere between hg
3dbc7b1ecaba and hg
8e3f6b5bf720, pytype stopped being able
to infer the type for `_docket_file` and `compress()`. Lock those types in
before they get lost.
[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