devtools: Accomodate block-style copyright blocks
devtools: Accomodate block-style copyright blocks

Without this, `copyright_header.py report . verbose` reports:
-------------------------------------------------------------------------------
1 with unexpected copyright holder names
	./build_msvc/libsecp256k1_config.h
-------------------------------------------------------------------------------


Former-commit-id: 9c54954c20c93322d638b60494062480e2d300fd
syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin