Add missing license headers

asl/types/function.hpp

@@ -1,3 +1,7 @@
+// Copyright 2025 Steven Le Rouzic
+//
+// SPDX-License-Identifier: BSD-3-Clause
+
 #pragma once
 
 #include "asl/base/utility.hpp"

asl/types/function_ref.hpp

@@ -1,3 +1,7 @@
+// Copyright 2025 Steven Le Rouzic
+//
+// SPDX-License-Identifier: BSD-3-Clause
+
 #pragma once
 
 #include "asl/base/utility.hpp"

asl/types/function_ref_tests.cpp

@@ -1,3 +1,7 @@
+// Copyright 2025 Steven Le Rouzic
+//
+// SPDX-License-Identifier: BSD-3-Clause
+
 #include "asl/testing/testing.hpp"
 #include "asl/types/function_ref.hpp"
 

asl/types/function_tests.cpp

@@ -1,3 +1,7 @@
+// Copyright 2025 Steven Le Rouzic
+//
+// SPDX-License-Identifier: BSD-3-Clause
+
 #include "asl/testing/testing.hpp"
 #include "asl/types/function.hpp"