Update markdown-features-react.mdx

mdx is using v2

website/docs/guides/markdown-features/markdown-features-react.mdx

@@ -15,7 +15,7 @@ import styles from './markdown-features-react.module.css';
 
 ## Using JSX in Markdown {#using-jsx-in-markdown}
 
-Docusaurus has built-in support for [MDX v1](https://mdxjs.com/), which allows you to write JSX within your Markdown files and render them as React components.
+Docusaurus has built-in support for [MDX v2](https://mdxjs.com/), which allows you to write JSX within your Markdown files and render them as React components.
 
 :::note