Make it clear how to debug

Nowhere in the documentation of this plugin that I could find did it explain how you can debug in VSCode. That's an awful oversight, because even if this plugin does ship the debug feature by itself, this is where most people will end up when they try to use Rust in VSCode. I just spent 15 minutes on Google trying to piece together which extensions were needed (despite having installed Rust on another computer a few months back), what I needed in my launch.json, my cargo.toml... And of course plenty of people give plenty of different solutions, because it's the internet.

Please update the readme of this plugin to provide a link to a md document explaining what is the recommended setup to debug Rust in VSCode. Having such a high barrier to entry does this beautiful language absolutely no favors.

Start by locating the plugin README and its documentation structure. Review the recommended Rust debugging setup for VSCode, including required extensions, launch.json, and Cargo.toml, then add a Markdown guide and link it from the README; done means newcomers can find one authoritative setup path.