fix license header

Signed-off-by: olivier lamy <oliver.lamy@gmail.com>

jetty-documentation/src/main/asciidoc/distribution-guide/startup/start-jar.adoc

@@ -1,18 +1,18 @@
 //
 // ========================================================================
 // Copyright (c) 1995-2020 Mort Bay Consulting Pty Ltd and others.
-//  ========================================================================
-//  All rights reserved. This program and the accompanying materials
-//  are made available under the terms of the Eclipse Public License v1.0
-//  and Apache License v2.0 which accompanies this distribution.
 //
-//      The Eclipse Public License is available at
+// This program and the accompanying materials are made available under
-//      http://www.eclipse.org/legal/epl-v10.html
+// the terms of the Eclipse Public License 2.0 which is available at
+// https://www.eclipse.org/legal/epl-2.0
 //
-//      The Apache License v2.0 is available at
+// This Source Code may also be made available under the following
-//      http://www.opensource.org/licenses/apache2.0.php
+// Secondary Licenses when the conditions for such availability set
+// forth in the Eclipse Public License, v. 2.0 are satisfied:
+// the Apache License v2.0 which is available at
+// https://www.apache.org/licenses/LICENSE-2.0
 //
-//  You may elect to redistribute this code under either of these licenses.
+// SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
 // ========================================================================
 //