docs(ui5-menu-item): update 09-accessibility.md (#9410)

The Accessibility documentation is being updated with changes introduced by PR #9333 

* `accessibilityAttributes` property introduced in `ui5-menu-item` component

Related to: #9333

docs/2-advanced/09-accessibility.md

@@ -185,6 +185,7 @@ The `accessibilityAttributes` property is currently supported in:
 `accessibilityAttributes` is also supported for composite components, where the application can enrich the accessibility of elements inside the component. For a more detailed information check the documentation of the property in:
 * [FlexibleColumnLayout](https://sap.github.io/ui5-webcomponents/nightly/components/fiori/FlexibleColumnLayout/)
 * [ShellBar](https://sap.github.io/ui5-webcomponents/nightly/components/fiori/ShellBar/)
+* [MenuItem](https://sap.github.io/ui5-webcomponents/nightly/components/MenuItem/)
 
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