Update SAML 2.0 Metadata URL Docs

Closes gh-9133

Author: jzheaux

docs/manual/src/docs/asciidoc/_includes/servlet/saml2/saml2-login.adoc

@@ -1025,6 +1025,15 @@ This is often as simple as finding the correct form field to supply the metadata
 By default, the metadata endpoint is `+/saml2/service-provider-metadata/{registrationId}+`.
 You can change this by calling the `setRequestMatcher` method on the filter:
 
+[source,java]
+----
+filter.setRequestMatcher(new AntPathRequestMatcher("/saml2/metadata/{registrationId}", "GET"));
+----
+
+ensuring that the `registrationId` hint is at the end of the path.
+
+Or, if you have registered a custom relying party registration resolver in the constructor, then you can specify a path without a `registrationId` hint, like so:
+
 [source,java]
 ----
 filter.setRequestMatcher(new AntPathRequestMatcher("/saml2/metadata", "GET"));