test: use `hg debugrequires` instead of `cat` in some tests This give the "same" result, while taking in account that the requirement file might be in different location, like what `share-safe` is doing. Differential Revision: https://phab.mercurial-scm.org/D11895

[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