fixup - outdated todo comment

nexus/src/internal_api/http_entrypoints.rs

@@ -286,7 +286,9 @@ async fn cpapi_instances_put(
 }
 
 /// Asynchronously report the successful result of certain instance_put calls
-/// (such as the potentially long-running one made during instance creation)
+/// (such as the potentially long-running one made during instance creation).
+/// If Nexus has already marked the instance as failed, this returns `TimedOut`
+/// so the sled-agent making the request knows to terminate the instance.
 #[endpoint {
      method = PUT,
      path = "/instances/{instance_id}/creation-success",
@@ -302,9 +304,6 @@ async fn cpapi_handle_instance_put_success(
     let result = Ok(instance_state.into_inner());
     let opctx = crate::context::op_context_for_internal_api(&rqctx).await;
     let handler = async {
-        // TODO: if instance_handle_creation_result errors because nexus gave
-        // up waiting and marked the instance as failed, tell sled-agent to
-        // destroy the instance
         nexus
             .instance_handle_creation_result(&opctx, &path.instance_id, result)
             .await