Update docs changelog (for PR #57247) (#57282)

Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>
Co-authored-by: Sophie <[email protected]>

Author: 3 people

CHANGELOG.md

@@ -1,5 +1,13 @@
 # Docs changelog
 
+**26 August 2025**
+
+xAI Grok Code Fast 1 is now available in public preview for GitHub Copilot. Grok Code Fast 1 is slowly rolling out to all paid Copilot plans and you will be able to access the model in Visual Studio Code (Agent, Ask, and Edit modes).
+
+See [Supported AI models in GitHub Copilot](https://docs.github.com/en/copilot/reference/ai-models/supported-models).
+
+<hr>
+
 **15 August 2025**
 
 When interacting with the GitHub MCP server for a public repository, push protection blocks secrets from appearing in AI-generated responses and also prevents secrets from being included in any actions you perform, such as creating an issue.