tests/test-check-rust-format.t

rust: use new revlog configs in all revlog opening code

This centralizes the more complex logic needed for the upcoming code
and creates stronger APIs with fewer booleans.

We also reuse `RevlogType` where needed.

#require rustfmt test-repo

  $ . "$TESTDIR/helpers-testrepo.sh"

  $ cd "$TESTDIR"/..

Warning: Keep this in sync with hghave.py
  $ RUSTFMT=$(rustup which --toolchain nightly-2024-07-16 rustfmt)
  $ for f in `testrepohg files 'glob:**/*.rs'` ; do
  >   $RUSTFMT --check --edition=2021 --unstable-features --color=never $f
  > done