revlog: move the nodemap into the index object (for pure)
This make the pure code closer to the C extension one. The ultimate goal is to
merge the two into a single object and offer a unified API. This changeset
focus on gathering the data on the same object.
For now the code for `revlogoldindex` and `BaseIndexObject` index object are
quite similar. However, there will be larger divergence later on, so I don't
think is worth doing a base case.
This work is part of a refactoring to unify the revlog index and the nodemap.
This unification prepare the use of a persistent nodemap.
Differential Revision: https://phab.mercurial-scm.org/D7313
[tool.black]
line-length = 80
exclude = '''
build/
| wheelhouse/
| dist/
| packages/
| \.hg/
| \.mypy_cache/
| \.venv/
| mercurial/thirdparty/
| contrib/python-zstandard/
'''
skip-string-normalization = true
quiet = true