fix(lsp): keep rust-analyzer's developer notices out of notifications

A rust-analyzer built from source reports its own slow main-loop turns
("overly long loop turn took …") as error messages meant for its developers.
They are logged now instead of shown as error notifications.

crates/ide-lsp/src/handler.rs

@@ -136,6 +136,12 @@ impl ClientHandler {
 
     fn show_message(&self, mgr: &LspManager, params: &Value) {
         let text = params.get("message").and_then(Value::as_str).unwrap_or_default().to_owned();
+        // rust-analyzer built from source reports its own slow main-loop turns as errors, meant for
+        // its developers (`poke_rust_analyzer_developer`); nothing for the user to act on.
+        if text.starts_with("overly long loop turn") {
+            tracing::warn!("[{}] {text}", self.server.name);
+            return;
+        }
         let level = match params.get("type").and_then(Value::as_u64) {
             Some(1) => NotifyLevel::Error,
             Some(2) => NotifyLevel::Warning,

crates/ide-lsp/tests/mock_server.rs

@@ -954,6 +954,11 @@ async fn apply_edit_hook_and_server_requests() {
     assert_eq!(v, Value::Null);
     assert!(peer.request::<_, Value>("unknown/method", Value::Null, None).await.is_err());
 
+    peer.notify(
+        "window/showMessage",
+        json!({ "type": 1, "message": "overly long loop turn took 113ms (event handling took 95ms): PrimeCaches" }),
+    )
+    .unwrap();
     peer.notify("window/showMessage", json!({ "type": 2, "message": "careful" })).unwrap();
     peer.notify("window/showMessage", json!({ "type": 3, "message": "info only" })).unwrap();
     peer.notify("window/logMessage", json!({ "type": 1, "message": "log" })).unwrap();
@@ -962,7 +967,10 @@ async fn apply_edit_hook_and_server_requests() {
     })
     .await;
     let notifies = h.events.lock().iter().filter(|e| matches!(e, IdeEvent::Notify { .. })).count();
-    assert_eq!(notifies, 2, "showMessageRequest error + showMessage warning; info is not surfaced");
+    assert_eq!(
+        notifies, 2,
+        "showMessageRequest error + showMessage warning; info and rust-analyzer's developer notices are not surfaced"
+    );
 
     // Dynamically registered capability is now usable.
     s.respond(