Add file header blocks to cpp files

Right justify mode selector in optional.cpp
Add block to test_types.cpp

Author: steve-downey

src/Beman/Optional26/optional.cpp

@@ -1,4 +1,4 @@
-// src/Beman/Optional26/optional.cpp -*-C++-*-
+// src/Beman/Optional26/optional.cpp                                  -*-C++-*-
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 
 #include <Beman/Optional26/optional.hpp>

src/Beman/Optional26/tests/test_types.cpp

@@ -1 +1,4 @@
+// src/Beman/Optional26/test/test_types.cpp                           -*-C++-*-
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
 #include <Beman/Optional26/tests/test_types.hpp>