rust-hg-path: add useful methods to `HgPath`
This changeset introduces the use of the `pretty_assertions` crate for easier
to read test output.
Differential Revision: https://phab.mercurial-scm.org/D7867
rust-pathauditor: add Rust implementation of the `pathauditor`
It does not offer the same flexibility as the Python implementation, but
should check incoming paths just as well.
Differential Revision: https://phab.mercurial-scm.org/D7866
py3: catch AttributeError too with ImportError
Looks like py3 raises AttributeError instead of ImportError. This is caught on
windows.
Differential Revision: https://phab.mercurial-scm.org/D7965