docs: Fix link to overview page (#3625)

Author: manuzhang

docs/source/index.md

@@ -86,7 +86,7 @@ To get started with Apache DataFusion Comet, follow the
 [DataFusion Slack and Discord channels](https://datafusion.apache.org/contributor-guide/communication.html) to connect
 with other users, ask questions, and share your experiences with Comet.
 
-Follow [Apache DataFusion Comet Overview](https://datafusion.apache.org/comet/user-guide/overview.html) to get more detailed information
+Follow [Apache DataFusion Comet Overview](https://datafusion.apache.org/comet/about/index.html) to get more detailed information
 
 ## Contributing