doc: don't use mutable default arguments It appears our mutable default arguments checker doesn't find arguments not on the first line of a function definition :( The arguments aren't used, so the default value is irrelevant. I found this when blackening this script in a future commit. Differential Revision: https://phab.mercurial-scm.org/D7445

[tool.black]
line-length = 80
exclude = '''
build/
| wheelhouse/
| dist/
| packages/
| \.hg/
| \.mypy_cache/
| \.venv/
| mercurial/thirdparty/
| contrib/python-zstandard/
'''
skip-string-normalization = true
quiet = true