Support env!("OUT_DIR") in include! macro calls in experimental mode. So now the plugin supports all code insight features (highlighting, navigation, completion, etc.) for code generated while compilation in most cases. Under the hood, it uses the output of cargo build --build-plan command to get value of OUT_DIR variable. Note, this feature is disabled by default because found out that cargo build --build-plan forces next build command to recompile whole project (including dependencies). To turn it on just enable org.rust.cargo.fetch.out.dir option in Experimental Features dialog.