Editor option to run the language server from cargo project

[udoprog]

This introduces another editor extension option which allows you to set a cargo package that should be used as the CLI entrypoint.

It tries to build the entrypoint (currently in debug mode) and capture the build artifact to use as a language server. This is then called:

• <bin> --version - to see if it can be executed.
• <bin> languageserver - to run the languageserver.

The latter is supported by anything that implements a CLI entrypoint. This allows (among other things) to more easily specify a server which uses a custom context. All you really need to do is set up a package which looks like this (and add your own modules of course):

rune::cli::Entry::new()
    .about(format_args!("The Rune Language Interpreter {VERSION}"))
    .context(&mut |opts| {
        let mut c = rune_modules::with_config(opts.capture.is_none())?;

        if opts.experimental {
            c.install(rune_modules::experiments::module(opts.capture.is_none())?)?;
        }

        Ok(c)
    })
    .run();

If something goes wrong, an error like this is displayed:

Note that I had to rewrite parts of the CLI because suprisingly we did not support a --version option.

Another side effect is that this makes it super easy to work on the language server since it can be both reloaded and rebuilt in the editor as needed.