typing: fix a suppression directive that was mangled by black formatting
It looks like black is moving comments needed by pytype out of position, and
causing some things that should be disabled to be enforced anyway.
Differential Revision: https://phab.mercurial-scm.org/D10165
[tool.black]
line-length = 80
exclude = '''
build/
| wheelhouse/
| dist/
| packages/
| \.hg/
| \.mypy_cache/
| \.venv/
| mercurial/thirdparty/
'''
skip-string-normalization = true
quiet = true