update copyright 2024

docs/sefht.texi

src/lib/sefht/attr.c

src/lib/sefht/attr.h

src/lib/sefht/attr_data.h

src/lib/sefht/attr_static.c

src/lib/sefht/cms.c

src/lib/sefht/cms.h

src/lib/sefht/data.c

src/lib/sefht/data.h

src/lib/sefht/fragment.c

src/lib/sefht/fragment.h

src/lib/sefht/fragment_class.c

src/lib/sefht/fragment_data.c

src/lib/sefht/log.h

src/lib/sefht/macro.h

src/lib/sefht/node_fragment.c

src/lib/sefht/node_fragment.h

src/lib/sefht/sefht.h

src/lib/sefht/status.h

src/lib/sefht/text.c