Move copyright to the top of files.

src/ftxui/dom/border_test.cpp

@@ -1,3 +1,6 @@
+// Copyright 2022 Arthur Sonzogni. All rights reserved.
+// Use of this source code is governed by the MIT license that can be found in
+// the LICENSE file.
 #include <gtest/gtest.h>
 #include <string>  // for allocator, string
 
@@ -102,7 +105,3 @@ TEST(BorderTest, Window) {
 
 }  // namespace ftxui
 // NOLINTEND
-
-// Copyright 2022 Arthur Sonzogni. All rights reserved.
-// Use of this source code is governed by the MIT license that can be found in
-// the LICENSE file.