Call out participant detection api finalization

Author: joyceerhl

release-notes/v1_95.md

@@ -380,6 +380,10 @@ We have finalized our [`LanguageModelTool` API](https://code.visualstudio.com/ap
 
 The use of language model tools is complex, and this API does not hide that complexity. If you want to register a tool or make use of tools in your chat participant, we recommend starting with the API docs and the extension sample (TODO links).
 
+### Chat participant detection
+
+We have finalized our API for chat participant detection, which allows GitHub Copilot to automatically select your chat participant or participant command to handle a user's question. Please check out [our documentation](/api/extension-guides/chat.md#implement-participant-detection) for a detailed tutorial and recommendations.
+
 ### VS Code Speech
 
 The [VS Code Speech](https://marketplace.visualstudio.com/items?itemName=ms-vscode.vscode-speech) extension is updated to the August version of the [Azure Speech SDK](https://learn.microsoft.com/en-us/azure/ai-services/speech-service/releasenotes?tabs=speech-sdk#speech-sdk-140-2024-august-release) and comes with newer models for speech-to-text recognition. You should see improved results with this update for the [speech-to-text integrations in VS Code](https://code.visualstudio.com/docs/editor/voice), such as Copilot Chat.