react(getting-started): fix MDX – close OnboardingOption tags and complete Step 6 code

Author: codyde

docs/platforms/javascript/guides/react/getting-started.mdx

@@ -157,9 +157,7 @@ import * as Sentry from "@sentry/react";
   Alternatively, if you're using a class component, you can wrap your application
   with `Sentry.withErrorBoundary`. Find out more
   [here](features/error-boundary/#manually-capturing-errors).
-</Alert>
-
-<OnboardingOption optionId="performance">
+ </Alert>
 
 <OnboardingOption optionId="logs">
 
@@ -229,6 +227,8 @@ Sentry.init({
 
 </OnboardingOption>
 
+<OnboardingOption optionId="performance">
+
 ## Step 6: Custom Traces with Attributes
 
 [Tracing](/platforms/javascript/guides/react/tracing/) allows you to monitor interactions between multiple services or applications. Create custom spans to measure specific operations and add meaningful attributes. This helps you understand performance bottlenecks and debug issues with detailed context.
@@ -281,6 +281,8 @@ if (span) {
 }
 ```
 
+</OnboardingOption>
+
 ## Step 7: Avoid Ad Blockers With Tunneling (Optional)
 
 <PlatformContent includePath="getting-started-tunneling" />
@@ -354,4 +356,3 @@ To capture Redux state data, use `Sentry.createReduxEnhancer` when initializing
 - [Get support](https://sentry.zendesk.com/hc/en-us/)
 
 </Expandable>
-