docs: Update README.md twitter links (#10468)

README.md

@@ -10,7 +10,7 @@
 </div>
 
 <p align="center">
-  <a href="https://twitter.com/docusaurus"><img src="https://img.shields.io/twitter/follow/docusaurus.svg?style=social" align="right" alt="Twitter Follow" /></a>
+  <a href="https://x.com/docusaurus"><img src="https://img.shields.io/twitter/follow/docusaurus.svg?style=social" align="right" alt="Twitter Follow" /></a>
   <a href="#backers" alt="sponsors on Open Collective"><img src="https://opencollective.com/Docusaurus/backers/badge.svg" /></a>
   <a href="#sponsors" alt="Sponsors on Open Collective"><img src="https://opencollective.com/Docusaurus/sponsors/badge.svg" /></a>
   <a href="https://www.npmjs.com/package/@docusaurus/core"><img src="https://img.shields.io/npm/v/@docusaurus/core.svg?style=flat" alt="npm version"></a>