Changes to rust-project.json requires restarting language server

Hi,

We use rust-project.json for a non-Cargo project and a relatively minor issue is that whenever the generated rust-project.json file changes, rust-analyzer must be restarted for editor features to resume working.

I assumed this would require a relatively minor change so I tried adding "{}/**/rust-project.json" to list of files to be watched for changes. However, after trying out this change locally I still have to restart rust-analyzer for changes to take affect.

Is it feasible to have rust-analyzer automatically detect and re-configure when rust-project.json changes? If so, any ideas as to what other changes may be required to make this work? Happy to work on it.

At the very least it would be useful to have a pop-up whenever rust-project.json changes to prompt the user to restart the language server.

Start in crates/rust-analyzer/src/reload.rs, especially the watched-file list around lines 254-256, and trace how rust-project.json changes are handled. Determine what is needed for rust-analyzer to reconfigure automatically, or establish the restart-prompt behavior as an alternative. Done means changes to a generated rust-project.json no longer require a manual restart, or the user is clearly prompted to restart.