Update documentation link to Spring HATEOAS's method links

Prefer link to official HATEOAS documentation rather than linking to the Github project README.

Author: thokuest

src/main/asciidoc/customizing-json-output.adoc

@@ -29,6 +29,8 @@ public RepresentationModelProcessor<EntityModel<Person>> personProcessor() {
 ----
 ====
 
+IMPORTANT: The preceding example hard codes a link to `http://localhost:8080/people`. If you have a Spring MVC endpoint inside your app to which you wish to link, consider using Spring HATEOAS's https://docs.spring.io/spring-hateoas/docs/current/reference/html/#fundamentals.obtaining-links.builder.methods[`linkTo(...)`] method to avoid managing the URL.
+
 IMPORTANT: The preceding example hard codes a link to `http://localhost:8080/people`. If you have a Spring MVC endpoint inside your app to which you wish to link, consider using Spring HATEOAS's https://github.com/spring-projects/spring-hateoas#building-links-pointing-to-methods[`linkTo(...)`] method to avoid managing the URL.
 [[customizing-sdr.customizing-json-output.adding-links]]
 == Adding Links