commitctx: gather more code dealing with copy-in-extra
Now that we have a function that deal with the copy-in-extra special case, we
can gather more code meant to deal with this special case. Making the rest of
the code simpler.
[tool.black]
line-length = 80
exclude = '''
build/
| wheelhouse/
| dist/
| packages/
| \.hg/
| \.mypy_cache/
| \.venv/
| mercurial/thirdparty/
'''
skip-string-normalization = true
quiet = true