session.run does not fail gracefully when receiving a list as command to run

[stefanv]

Current Behavior

session.run(["pytests", "mypkg"]) results in a traceback.

Expected Behavior

One of the following options:

(a) The error is caught and a helpful message displayed.
(b) The list is correctly intepreted as a command.

Steps To Reproduce

import nox


@nox.session
def tests(session: nox.Session) -> None:
    session.run(["pytest", "foo"])

Environment

- OS: Linux
- Python: 3.11
- Nox: 2023.4.22

Anything else?

I would be happy to submit a PR to address the issue, once I know which solution is preferred.

[henryiii]

IMO a) is fine, it keeps the syntax and type hints simple, and you simply need to add a single character (*) to convert if you already have a list.