DATAJPA-1761 - Removed superfluous save from example code.

src/main/asciidoc/jpa.adoc

@@ -860,7 +860,7 @@ class UserManagementImpl implements UserManagement {
 
     for (User user : userRepository.findAll()) {
       user.addRole(role);
-      userRepository.save(user);
+      // note that no call to "save" is necessary since the entities are attached to the EntityManager
     }
 }
 ----