D7952: rust: add a README

[Alphare (Raphaël Gomès)]

Alphare added inline comments.
Alphare accepted this revision.

INLINE COMMENTS

> README.rst:27
> +  $ HGWITHRUSTEXT=cpython make tests # to run all tests
> +  $ (cd tests; HGWITHRUSTEXT=cpython ./run-tests.py) # only the .t
> +  $ ./hg debuginstall | grep rust # to validate rust is in use

I think you're missing the `-l` option for `run-tests.py`

> README.rst:34
>  
> -If you prefer a non-debug / release configuration::
> +Developing hg-core
> +==================

I would add a mention of using `cargo c(heck)` for faster iteration and using `cargo test --all` to run the Rust tests, but this patch is already good enough on its own.

REPOSITORY
  rHG Mercurial

CHANGES SINCE LAST ACTION
  https://phab.mercurial-scm.org/D7952/new/

REVISION DETAIL
  https://phab.mercurial-scm.org/D7952

To: valentin.gatienbaron, #hg-reviewers, Alphare
Cc: Alphare, mjpieters, mercurial-devel