message: order copyright lines by date
diff: /*
  Copyright 2015, 2016 OpenMarket Ltd
  Copyright 2017 New Vector Ltd
  -Copyright 2019, 2020 The Matrix.org Foundation C.I.C.
  Copyright 2019 Michael Telatynski <7t3chguy@gmail.com>
  +Copyright 2019, 2020 The Matrix.org Foundation C.I.C.
  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  