Mention discussions in CONTRIBUTING.md

CONTRIBUTING.md

@@ -28,6 +28,10 @@ opening an issue, read these pointers.
 - Be polite. Issues with an indignant or belligerent tone tend to be moved to the
   bottom of the pile.
 
+## Answering discussion questions
+
+Issues are only meant to track (likely) feature requests and bugs. We use [GitHub Discussions](https://github.com/xtermjs/xterm.js/discussions) for general Q&A as well as discussing possible features. If you want to help out, many questions get asked over at the [discussions page](https://github.com/xtermjs/xterm.js/discussions) which could use an expert as the core team is often stretched thin.
+
 ## Contributing code
 
 You can find issues to work on by looking at the [help wanted](https://github.com/xtermjs/xterm.js/issues?q=is%3Aissue+is%3Aopen+label%3A%22help+wanted%22) or [good first issue](https://github.com/xtermjs/xterm.js/issues?q=is%3Aissue+is%3Aopen+label%3A%22good+first+issue%22) issues. It's a good idea to comment on the issue saying that you're taking it, just in case someone else comes along and you duplicate work. Once you have your issue, here are the steps to contribute: