docs: clarify Ant Design ecosystem note

Author: afc163

README.md

@@ -4,6 +4,15 @@
   <p>💬 React mentions textarea with searchable suggestions and keyboard navigation.</p>
 </div>
 
+<p align="center">
+  <sub>
+    <a href="https://ant.design">
+      <img alt="Ant Design" src="https://gw.alipayobjects.com/zos/rmsportal/KDpgvguMpGfqaHPjicRK.svg" height="16">
+    </a>
+    Part of the Ant Design ecosystem.
+  </sub>
+</p>
+
 <div align="center">
 
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