narrowspec: add timing block for validating narrowspec This was showing up in an operation I was doing today, and I'd like to be able to get trace spans for it instead of just profiler samples. Differential Revision: https://phab.mercurial-scm.org/D12185

[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