rust-project.json not picked up by rust-analyzer on third_party code

I ran `bazel run @rules_rust//tools/rust_analyzer:gen_rust_project` and it generates a rust-project.json that provides LSP funcitonality for all first-party code. However, I have some vendored third-party dependencies that I would like to get LSP functionality for as well. Can this be done? I tried passing in @my_third_party//... to the list of targets when running gen_rust_project, but that only adds the targets in the exec root, so the LSP doesn't pick it up when editing the third-party code directly.

Even if I generate the rust-project.json specifically for the third_party code, that doesn't work because rust-analyzer picks up the wrong rust-project.json as far as I can tell.

Any thoughts on how to support this functionality? I'm happy to make PR to work once I have a path forward.

Thanks!