Copilot: Add preview note for Chat in Eclipse (#54763)

Author: hubwriter

content/copilot/using-github-copilot/copilot-chat/asking-github-copilot-questions-in-your-ide.md

@@ -422,6 +422,8 @@ To indicate whether a response was helpful, use {% octicon "thumbsup" aria-label
 
 {% eclipse %}
 
+{% data reusables.copilot.eclipse-public-preview-note %}
+
 ## Prerequisites
 
 {% data reusables.copilot.eclipse-prerequisites %}