debugdiscovery: add support for Json output
They are some pre-output that will be impractical, I'll take care of it in the
next changeset.
Differential Revision: https://phab.mercurial-scm.org/D10223
[tool.black]
line-length = 80
exclude = '''
build/
| wheelhouse/
| dist/
| packages/
| \.hg/
| \.mypy_cache/
| \.venv/
| mercurial/thirdparty/
'''
skip-string-normalization = true
quiet = true