Add whitespace after copyright header

Add an additional lines after the copyright header and before the
`package` declaration. This aligns with the style used by Spring
Framework.

Issue gh-8945

samples/javaconfig/messages/src/main/java/org/springframework/security/samples/config/DataConfiguration.java

@@ -13,6 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
 package org.springframework.security.samples.config;
 
 import javax.sql.DataSource;

samples/javaconfig/messages/src/main/java/org/springframework/security/samples/config/MessageWebApplicationInitializer.java

@@ -13,6 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
 package org.springframework.security.samples.config;
 
 import javax.servlet.Filter;

samples/javaconfig/messages/src/main/java/org/springframework/security/samples/config/RootConfiguration.java

@@ -13,6 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
 package org.springframework.security.samples.config;
 
 import org.springframework.context.annotation.ComponentScan;

samples/javaconfig/messages/src/main/java/org/springframework/security/samples/data/Message.java

@@ -13,6 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
 package org.springframework.security.samples.data;
 
 import java.util.Calendar;

samples/javaconfig/messages/src/main/java/org/springframework/security/samples/data/MessageRepository.java

@@ -13,6 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
 package org.springframework.security.samples.data;
 
 import org.springframework.data.repository.CrudRepository;

samples/javaconfig/messages/src/main/java/org/springframework/security/samples/mvc/DefaultController.java

@@ -13,6 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
 package org.springframework.security.samples.mvc;
 
 import org.springframework.stereotype.Controller;

samples/javaconfig/messages/src/main/java/org/springframework/security/samples/mvc/MessageController.java

@@ -13,6 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
 package org.springframework.security.samples.mvc;
 
 import javax.validation.Valid;

samples/javaconfig/messages/src/main/java/org/springframework/security/samples/mvc/config/WebMvcConfiguration.java

@@ -13,6 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
 package org.springframework.security.samples.mvc.config;
 
 import org.springframework.beans.factory.annotation.Autowired;