docs(js/react-router): Document createSentryHandleError

docs/platforms/javascript/guides/react-router/index.mdx

@@ -276,17 +276,11 @@ Update your `entry.server.tsx` file:
 +  createReadableStreamFromReadable,
 +});
 
-export default handleRequest;
-
-export const handleError: HandleErrorFunction = (error, { request }) => {
-  // React Router may abort some interrupted requests, don't log those
-  if (!request.signal.aborted) {
-+   Sentry.captureException(error);
-    // optionally log the error so you can see it
-    console.error(error);
-  }
-};
+ export default handleRequest;
 
++export const handleError = Sentry.createSentryHandleError({
++  logErrors: false
++});
 
 // ... rest of your server entry
 ```
@@ -369,6 +363,35 @@ export default wrapSentryHandleRequest(handleRequest);
 
 </Expandable>
 
+<Expandable title="Do you need to customize your handleError function?">
+  If you have custom logic in your `handleError` function, you'll need to capture errors manually:
+
+```tsx {12}
+import {
+  getMetaTagTransformer,
+  wrapSentryHandleRequest,
+} from "@sentry/react-router";
+// ... other imports
+
+export function handleError(
+  error: unknown,
+  {
+    request,
+    params,
+    context,
+  }: LoaderFunctionArgs | ActionFunctionArgs
+) {
+  if (!request.signal.aborted) {
+    Sentry.captureException(error);
+    console.error(formatErrorForJsonLogging(error));
+  }
+}
+
+// ... rest of your entry.server.ts file
+```
+
+</Expandable>
+
 ### Update Scripts
 
 Since React Router is running in ESM mode, you need to use the `--import` command line options to load our server-side instrumentation module before the application starts.