How would this feature be useful?

I think most people will use the nox.project.load_toml function (added in #811) with their pyproject.toml. In fact, the name of the function itself suggests loading from a TOML.

Describe the solution you'd like

I would update the function's signature:

with:

def load_toml(filename: os.PathLike[str] | str = "pyproject.toml") -> dict[str, Any]: 

or set the default to None and evaluate the file location from pwd:

def load_toml(filename: os.PathLike[str] | str | None = None) -> dict[str, Any]: 
    if filename is None:
        filename = Path.cwd() / "pyproject.toml"

    # ...

Describe alternatives you've considered

Alternatively, the path to the pyproject.toml can be set via nox.options.

Anything else?

No response