Add nice license headers to files in examples/ and fuzzing/

Related to #2730

fuzzing/NullOStream.cpp

@@ -1,3 +1,11 @@
+
+//              Copyright Catch2 Authors
+// Distributed under the Boost Software License, Version 1.0.
+//   (See accompanying file LICENSE.txt or copy at
+//        https://www.boost.org/LICENSE_1_0.txt)
+
+// SPDX-License-Identifier: BSL-1.0
+
 #include "NullOStream.h"
 
 void NullOStream::avoidOutOfLineVirtualCompilerWarning()

fuzzing/NullOStream.h

@@ -1,3 +1,11 @@
+
+//              Copyright Catch2 Authors
+// Distributed under the Boost Software License, Version 1.0.
+//   (See accompanying file LICENSE.txt or copy at
+//        https://www.boost.org/LICENSE_1_0.txt)
+
+// SPDX-License-Identifier: BSL-1.0
+
 #pragma once
 
 #include <ostream>

fuzzing/fuzz_TestSpecParser.cpp

@@ -1,4 +1,10 @@
-//License: Boost 1.0
+
+//              Copyright Catch2 Authors
+// Distributed under the Boost Software License, Version 1.0.
+//   (See accompanying file LICENSE.txt or copy at
+//        https://www.boost.org/LICENSE_1_0.txt)
+
+// SPDX-License-Identifier: BSL-1.0
 //By Paul Dreik 2020
 
 #include <catch2/internal/catch_test_spec_parser.hpp>

fuzzing/fuzz_XmlWriter.cpp

@@ -1,4 +1,10 @@
-//License: Boost 1.0
+
+//              Copyright Catch2 Authors
+// Distributed under the Boost Software License, Version 1.0.
+//   (See accompanying file LICENSE.txt or copy at
+//        https://www.boost.org/LICENSE_1_0.txt)
+
+// SPDX-License-Identifier: BSL-1.0
 //By Paul Dreik 2020
 
 #include <catch2/internal/catch_xmlwriter.hpp>

fuzzing/fuzz_textflow.cpp

@@ -1,4 +1,10 @@
-//License: Boost 1.0
+
+//              Copyright Catch2 Authors
+// Distributed under the Boost Software License, Version 1.0.
+//   (See accompanying file LICENSE.txt or copy at
+//        https://www.boost.org/LICENSE_1_0.txt)
+
+// SPDX-License-Identifier: BSL-1.0
 //By Paul Dreik 2020
 
 #include <catch2/internal/catch_textflow.hpp>