fix(transport): satisfy nightly rustfmt and build test ServerInfo via ::new (#857)

- Wrap the synthetic-cancellation construction to match `cargo +nightly
  fmt`.
- `ServerInfo` is `#[non_exhaustive]`; construct it in the test with
  `ServerInfo::new(..)` instead of a struct literal.

Verified locally: `cargo +nightly fmt --all -- --check` clean and the
regression test passes (disconnect cancels the in-flight request).

Author: ameyypawar

crates/rmcp/src/transport/streamable_http_server/session/local.rs

@@ -242,8 +242,9 @@ impl<S> Drop for CancelOnDisconnect<S> {
             method: CancelledNotificationMethod,
             extensions: Default::default(),
         };
-        let message =
-            ClientJsonRpcMessage::notification(ClientNotification::CancelledNotification(cancelled));
+        let message = ClientJsonRpcMessage::notification(
+            ClientNotification::CancelledNotification(cancelled),
+        );
         // `Drop` cannot await; deliver on the session's control channel without
         // blocking. If the channel is momentarily full the request is not
         // cancelled early, but the session keep-alive/idle timeout still reaps

crates/rmcp/tests/test_streamable_http_disconnect_cancel.rs

@@ -29,10 +29,7 @@ struct DisconnectServer {
 
 impl ServerHandler for DisconnectServer {
     fn get_info(&self) -> ServerInfo {
-        ServerInfo {
-            capabilities: ServerCapabilities::builder().enable_tools().build(),
-            ..Default::default()
-        }
+        ServerInfo::new(ServerCapabilities::builder().enable_tools().build())
     }
 
     async fn call_tool(