dirstate: simplify the shelve hack to not go through the disk
We already have the data in memory, so why not simply keep the data in memory?
This avoid abusing the `savebackup/restorebackup` logic and will make our life
easier.
[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