Prioritize use of ruff commands installed in the environment

[yaegassy]

Create a virtual environment (project) with venv, poetry, etc., activated the virtual environment, and install the ruff command inside the virtual environment.

Currently, To use the ruff command installed in this virtual environment with ruff-lsp, explicitly set the ruff path or interpreter (settings) to the language server. This must be done every time for all projects that use ruff.

If the above settings are not made, the ruff command installed with ruff-lsp will be used. It may be different from the version of the ruff command installed in your project.

I added code to detect the ruff command installed in the project and use it preferentially.

[ruby0b]

As explained in #68, I'm packaging ruff-lsp for nixpkgs and depend on this PR getting merged for the package to work.
A new pypi release containing the change would also be appreciated.

@charliermarsh

[charliermarsh]

This looks reasonable, sorry for the delay.