Mention rust-analyzer.cargo.loadOutDirsFromCheck setting in README

Fixes #512

README.md

@@ -36,6 +36,9 @@ contains the tools to build clients and servers from [`protobuf`] definitions.
 Examples can be found in [`examples`] and for more complex scenarios [`interop`]
 may be a good resource as it shows examples of many of the gRPC features.
 
+If you're using [rust-analyzer] we recommend you set `"rust-analyzer.cargo.loadOutDirsFromCheck": true` to correctly load
+the generated code.
+
 ### Rust Version
 
 `tonic` currently works on rust `1.39` and above as it requires support for the `async_await`
@@ -110,3 +113,4 @@ terms or conditions.
 [routeguide-tutorial]: https://github.com/hyperium/tonic/blob/master/examples/routeguide-tutorial.md
 [helloworld-tutorial]: https://github.com/hyperium/tonic/blob/master/examples/helloworld-tutorial.md
 [healthcheck]: https://github.com/grpc/grpc/blob/master/doc/health-checking.md
+[rust-analyzer]: https://rust-analyzer.github.io