errors: use exit code 10 for parse errors
Now that `ParseError`s raised while reading the config file has been
converted into `ConfigError`s, the remaining parse errors should all
be "input errors" (i.e. exit code 10), according to
https://www.mercurial-scm.org/wiki/ErrorCategoriesPlan.
Differential Revision: https://phab.mercurial-scm.org/D9332
[tool.black]
line-length = 80
exclude = '''
build/
| wheelhouse/
| dist/
| packages/
| \.hg/
| \.mypy_cache/
| \.venv/
| mercurial/thirdparty/
'''
skip-string-normalization = true
quiet = true