chore: Prepare for Rust edition bump to 2024 (without autofix) (#27791)

Successor to #27779 - in this PR I've applied changes manually, without
futzing with if let lifetimes at all.

Release Notes:

- N/A

crates/collab/src/rpc.rs

@@ -724,7 +724,7 @@ impl Server {
         system_id: Option<String>,
         send_connection_id: Option<oneshot::Sender<ConnectionId>>,
         executor: Executor,
-    ) -> impl Future<Output = ()> {
+    ) -> impl Future<Output = ()> + use<> {
         let this = self.clone();
         let span = info_span!("handle connection", %address,
             connection_id=field::Empty,