typing: add type hints to the prompt methods in mercurial/ui.py
The @overloads allow for the callers that pass a non-None `default` to not have
to worry about handling a None return to appease pytype.
[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