docs: update release note

website/blog/2023-08-13-v1.8.9.md

@@ -39,3 +39,4 @@ tags: [Release Note]
 - Fixed the bug of abnormal size when multiple avatars were rendered at the same time
 - Increase the optimization of offline icon sorting to reduce meaningless updates
 - Optimize the experience of sending messages under low-speed network
+- Optimize DM message support sorting by recent message

website/i18n/zh-Hans/docusaurus-plugin-content-blog/2023-08-13-v1.8.9.md

@@ -39,3 +39,4 @@ tags: [版本发布]
 - 修复多个头像同时渲染时大小异常的bug
 - 增加离线图标排序优化，减少无意义的更新
 - 优化在低速网络下发送消息的体验
+- 优化私信支持按照最近发言排序