Update prompting.mdx (#20448)

Author: thomasgauvin

src/content/docs/workers/get-started/prompting.mdx

@@ -40,6 +40,7 @@ You can use the prompt in several ways:
 	* Cursor: add the prompt to [your Project Rules](https://docs.cursor.com/context/rules-for-ai)
 	* Zed: use [the `/file` command](https://zed.dev/docs/assistant/assistant-panel) to add the prompt to the Assistant context.
 	* Windsurf: use [the `@-mention` command](https://docs.codeium.com/chat/overview) to include a file containing the prompt to your Chat.
+  * GitHub Copilot: create the [`.github/copilot-instructions.md`](https://docs.github.com/en/copilot/customizing-copilot/adding-repository-custom-instructions-for-github-copilot) file at the root of your project and add the prompt.
 
 :::note