Change Chat section header to 'Chat 2'

Updated the Chat section header in README.md.

Author: leehnhung1

README.md

@@ -3,7 +3,7 @@
 [GitHub Copilot](https://github.com/features/copilot) is an AI pair programmer
 tool that helps you write code faster and smarter. Copilot for Xcode is an Xcode extension that provides inline coding suggestions as you type and a chat assistant to answer your coding questions.
 
-## Chat
+## Chat 2
 
 GitHub Copilot Chat provides suggestions to your specific coding tasks via chat.
 <img alt="Chat of GitHub Copilot for Xcode" src="./Docs/Images/chat_dark.gif" width="800" />
@@ -153,4 +153,4 @@ forum](https://github.com/orgs/community/discussions/categories/copilot).
 Thank you to @intitni for creating the original project that this is based on.
 
 Attributions can be found under About when running the app or in
-[Credits.rtf](./Copilot%20for%20Xcode/Credits.rtf).
+[Credits.rtf](./Copilot%20for%20Xcode/Credits.rtf).