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

remoting/src/main/java/org/springframework/security/remoting/dns/package-info.java

@@ -13,6 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
 /**
  * DNS resolution.
  */

remoting/src/main/java/org/springframework/security/remoting/httpinvoker/package-info.java

@@ -13,6 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
 /**
  * Enables use of Spring's <code>HttpInvoker</code> extension points to present the
  * <code>principal</code> and <code>credentials</code> located in the

remoting/src/main/java/org/springframework/security/remoting/package-info.java

@@ -13,6 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
 /**
  * Remote client related functionality.
  */

remoting/src/main/java/org/springframework/security/remoting/rmi/package-info.java

@@ -13,6 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
 /**
  * Enables use of Spring's RMI remoting extension points to propagate the
  * <code>SecurityContextHolder</code> (which should contain an <code>Authentication</code>