docs(js): Add comments for RR code snippets (#13386)

Author: chargome

docs/platforms/javascript/guides/react/features/react-router/v6.mdx

@@ -15,7 +15,7 @@ To instrument your React Router, update your `Sentry.browserTracingIntegration`
 - Use `Sentry.wrapCreateBrowserRouterV6` for [`createBrowserRouter`](https://reactrouter.com/en/main/routers/create-browser-router) and [`createHashRouter`](https://reactrouter.com/en/main/routers/create-hash-router)
 - Use `Sentry.wrapCreateMemoryRouterV6` for [`createMemoryRouter`](https://reactrouter.com/en/main/routers/create-memory-router) (introduced in SDK version `8.50.0`)
 
-```javascript {2-8, 15-21, 26-33}
+```javascript {2-8, 15-21, 26-34}
 import React from "react";
 import {
   createBrowserRouter,
@@ -41,6 +41,7 @@ Sentry.init({
   tracesSampleRate: 1.0,
 });
 
+// Call this AFTER Sentry.init()
 const sentryCreateBrowserRouter =
   Sentry.wrapCreateBrowserRouterV6(createBrowserRouter);
 

docs/platforms/javascript/guides/react/features/react-router/v7.mdx

@@ -21,7 +21,7 @@ To instrument your React Router, update your `Sentry.browserTracingIntegration`
 - Use `Sentry.wrapCreateBrowserRouterV7` for [`createBrowserRouter`](https://reactrouter.com/en/main/routers/create-browser-router) and [`createHashRouter`](https://reactrouter.com/en/main/routers/create-hash-router)
 - Use `Sentry.wrapCreateMemoryRouterV7` for [`createMemoryRouter`](https://reactrouter.com/en/main/routers/create-memory-router) (introduced in SDK version `8.50.0`)
 
-```javascript {2-8, 15-21, 26-33}
+```javascript {2-8, 15-21, 26-34}
 import React from "react";
 import {
   createBrowserRouter,
@@ -47,6 +47,7 @@ Sentry.init({
   tracesSampleRate: 1.0,
 });
 
+// Call this AFTER Sentry.init()
 const sentryCreateBrowserRouter =
   Sentry.wrapCreateBrowserRouterV7(createBrowserRouter);