Simplify AuthorizeReturnObject Usage

While the proxy factory feature is cool, it's not needed for
this sample. We can point folks to the documentation to understand
when something like that is needed.

servlet/spring-boot/java/data/README.adoc

@@ -48,4 +48,6 @@ However, with `rob`, you'll also see `firstName` and `lastName` like so:
         }
     }
   ...
-```
+```
+
+Read more about the https://docs.spring.io/spring-security/reference/servlet/authorization/method-security.html#authorize-object[`@AuthorizeReturnObject`] and https://docs.spring.io/spring-security/reference/servlet/authorization/method-security.html#fallback-values-authorization-denied[]`@DeniedHandler`] in the Spring Security Reference.