Role descriptor link (#83753) (#85006)

Add a reference to the role descriptor

Co-authored-by: EdwynPe <[email protected]>

Author: nik9000

x-pack/docs/en/security/authentication/service-accounts.asciidoc

@@ -23,7 +23,7 @@ because they:
 
 * Do not rely on the <<native-realm,internal `native` realm>>, and aren't
 always required to rely on the `.security` index
-* Use a role descriptor named after the service account principal instead of
+* Use a <<security-api-create-api-key-request-body,role descriptor>> named after the service account principal instead of
 traditional roles
 * Support multiple credentials through service account tokens