Useful span names for incoming HTTP requests

Usually it's not possible to make span names dynamic, but the magic
otel.name attribute changes the span name in the OpenTelemetry tracing
backend.

src/main.rs

@@ -168,7 +168,7 @@ async fn run_server() -> io::Result<()> {
                     request.uri().path()
                 };
 
-                tracing::info_span!("http_request", %path, method = %request.method())
+                tracing::info_span!("http_request", otel.name = path, %path, method = %request.method())
             },
         ))
         .layer(axum::middleware::from_fn(unrecognized_method))