docs(coding-agent): update event bus docs - async errors now caught automatically

packages/coding-agent/docs/custom-tools.md

@@ -202,17 +202,7 @@ const unsubscribe = pi.events.on("other:event", (data) => {
 
 Events are session-scoped. Use namespaced channel names like `"toolname:event"` to avoid collisions.
 
-Handler errors are caught and logged. For async handlers, handle errors internally:
-
-```typescript
-pi.events.on("mytool:event", async (data) => {
-  try {
-    await doSomething(data);
-  } catch (err) {
-    console.error("Handler failed:", err);
-  }
-});
-```
+Handler errors (sync and async) are caught and logged.
 
 ### Sending Messages