consistency in dashes Vs underscores (e.g. "env-vars")

[smondet]

See an example of rare use of dashes:
https://github.com/ocaml/dune/blob/main/src/dune_rules/dune_env.ml#L200

This can make search in the documentation not great.

The env-vars field could just have an env_vars alias and be backwards compatible.

[maiste]

It seems indeed inconsistent. @rgrinberg was there a reason and, if no, do you think we should do have them both living in dune?

[rgrinberg]

There's no reason why it's this way. Adding an alias is fine here.