rust-index: add fast-path for getting a list of all heads as nodes
This avoids a lot of back-and-forth between Python and Rust. We forgo adding
a fast-path in the `filteredchangelog` case yet. If it shows up in profiling,
we might add the variant with a filter.
[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