Add missing character to NavigationView readme

Author: lucaasrojas

docs/extensions/NavigationView.md

@@ -7,7 +7,7 @@ keywords: windows 10, uwp, windows community toolkit, uwp community toolkit, uwp
 
 # NavigationView Styles
 
-[!NOTE] The NavigationView extension will be removed in a future major release.
+> [!NOTE] The NavigationView extension will be removed in a future major release.
 
 <!-- Describe your control -->
 The [NavigationView Styles](https://docs.microsoft.com/en-us/windows/uwpcommunitytoolkit/extensions/navigationview) are a set of styles and extensions to reskin a `NavigationView` to look and behave like the `Activity Bar` and `Side Bar` in *Visual Studio Code*.