Update Part-3.md

Removing @ from @() => GetDeleteConfirmationMessage(context) as it is wrong and doesn't need an @ at the front of ()

docs/en/Tutorials/Part-3.md

@@ -1386,7 +1386,7 @@ Open the `Books.razor` page and add the following `EntityAction` under the "Edit
 <EntityAction TItem="BookDto"
               Text="@L["Delete"]"
               Clicked="() => DeleteEntityAsync(context)"
-              ConfirmationMessage="@() => GetDeleteConfirmationMessage(context)" />
+              ConfirmationMessage="() => GetDeleteConfirmationMessage(context)" />
 ````
 
 * `DeleteEntityAsync` is defined in the base class that deletes the entity by performing a call to the server.