Update mediator.mdx

Author: aritchie

src/content/docs/release-notes/mediator.mdx

@@ -10,6 +10,7 @@ import RN from '/src/components/ReleaseNote.astro';
 ### v4.10 - TBD
 <RN type="feature">New contract key generator - sample below</RN>
 <RN type="feature">Re-releasing standalone Sentry library due to AOT not being supported on MAUI via Sentry.Diagnostics</RN>
+<RN type="enhancement" breaking={true}>MAUI storage services like offline now use the cache directory</RN>
 <RN type="enhancement">New RuntimeEventRegistration service that you can add event handlers to at runtime dynamically</RN>
 
 New Contract Key Generator