Remove extra "not" from sentence (#6463)

Author: xivanku

src/platform-includes/getting-started-primer/javascript.nextjs.mdx

@@ -13,7 +13,7 @@ Features:
 - [Breadcrumbs](/platforms/javascript/enriching-events/breadcrumbs/) created for outgoing HTTP request with XHR and Fetch, and console logs
 - [Release health](/product/releases/health/) for tracking crash-free users and sessions
 - Automatic [Performance Monitoring](/product/performance/) for both the client and server, from version `6.5.0`
-- Errors and Performance support for [Middleware](https://vercel.com/docs/concepts/functions/edge-middleware) and [Edge routes](https://vercel.com/docs/concepts/functions/edge-functions) in Vercels experimental edge runtime. Due to complexities with the experimental runtime, some features of errors like stacktraces may not not be as expected.
+- Errors and Performance support for [Middleware](https://vercel.com/docs/concepts/functions/edge-middleware) and [Edge routes](https://vercel.com/docs/concepts/functions/edge-functions) in Vercels experimental edge runtime. Due to complexities with the experimental runtime, some features of errors like stacktraces may not be as expected.
 
 Under the hood the SDK relies on our [React SDK](/platforms/javascript/guides/react/) on the frontend and [Node SDK](/platforms/node) on the backend, which makes all features available in those SDKs also available in this SDK.
 Using a [custom server](https://nextjs.org/docs/advanced-features/custom-server) is currently not supported.