Fix wrong import for nextjs pages router

Author: rene-demonsters

src/content/docs/back-end/next-js-pages-router.mdx

@@ -52,7 +52,7 @@ execute the following steps manually.
 
       ```tsx
         import type { AppProps } from 'next/app'
-        import { StringTaleProvider } from "@stringtale/next"
+        import { StringtaleProvider } from "@stringtale/react"
         import "@stringtale/react/styles.css"
 
         export default function MyApp({ Component, pageProps }: AppProps) {