rust/rhg/README.md

run-test: act that we requires MSYS to run the test on Windows

If this ever change we can drop that constrains, however for now it seems clear
to be clear about this limitation.

Differential Revision: https://phab.mercurial-scm.org/D11080

# rhg

This project provides a fastpath Rust implementation of the Mercurial (`hg`)
version control tool.