Update 11.9.md

Author: quinntracy

content/en/docs/releasenotes/studio-pro/11/11.9.md

@@ -61,6 +61,7 @@ For more information, see [Portable App Distribution](/developerportal/deploy/po
 - We released a modernized JavaScript Action Editor into public beta. You can enable the new editor in Studio Pro under **Preferences** > **New features**. For more information, see [JavaScript Actions](refguide/javascript-actions/).
 - We added support for XPath constraints in nanoflow database retrieves to follow associations from a variable, so comparisons like `$var/Association = $var` now work.
 - We added a client API to activate a waiting service worker. You can now use `skipWaiting` from `mx-api/pwa`, which resolves once the new service worker takes control. This is useful when you want to update to a new application version without waiting for all tabs to close. To fully apply the update, the page should be reloaded so all resources are loaded from the new service worker.
+- Web Extensions can now raise consistency errors in MxBuild. This introduces Deno to the MxBuild tool chain. For troubleshooting details, see the *Troubleshooting* section of [MxBuild](/refguide/mxbuild/#troubleshooting).
 
 ### Improvements