re2: byteify some regex used to get check re2 availability
Changeset 687b865b95ad failed to properly byteify this because it was a raw
string. This went undetected so far because re2 does not seems to be widely
tested.
Differential Revision: https://phab.mercurial-scm.org/D10064
[tool.black]
line-length = 80
exclude = '''
build/
| wheelhouse/
| dist/
| packages/
| \.hg/
| \.mypy_cache/
| \.venv/
| mercurial/thirdparty/
'''
skip-string-normalization = true
quiet = true