Use Python to invoke ruff instead of binary

[anakinxc]

When user installs ruff via pip install --user, ruff binary is usually not on system path.

Directly invoke ruff will cause error No such file or directory: 'ruff', ask Python to invoke the python one is an safer approach.

[tpppppub]

Hit the same issue

[akaihola]

Thanks @anakinxc and @tpppppub!

Won't this then break --formatter=ruff for those who like to install Ruff using an operating system package manager or manually?

If that's the case, what options do we have? The following come to mind:

• first see if the ruff Python package is installed, and only use python -m ruff if that's the case, otherwise just ruff
• first see if the ruff binary is found in PATH, and use just ruff if that's the case, otherwise try python -m ruff
• just use ruff, and if it fails, try python -m ruff
• use python -m ruff, and if it fails, try just ruff
• ...other?

[anakinxc]

• just use ruff, and if it fails, try python -m ruff

Personally, I think this one is a better solution