Allow nox test to trigger session test

[bluss]

How would this feature be useful?

It's shorter to type and less stumbling on the keyboard to write nox test than to do nox -s test. This would make nox a rival to other task running solutions (make, poe, just, and so on)

Describe the solution you'd like

It could be opt-in.

Either (easier) nox.options.run_session_by_name = True which means that nox test will look for session(s) called test and run them, or more convoluted would be to let posargs be session.posargs if there are no other arguments, and the user has to set up a default session and dispatch to sessions by name from there themselves.

Describe alternatives you've considered

Typing nox -s test is an alternative. The more punctuation, the less convenient, and - is punctuation.

The user could have a shell alias for alias nos="nox -s"; but this does not help with a "portable" nox setup where you invoke it as ./nox.

nox could be used for its own strengths, environment setup and parametrization, and a dedicated task runner could be used for short invocations, like make, poe, just which all allow make test and so on.

Anything else?

I didn't find any existing features in nox that cover this use case.