build: CMake's `verify_header_sets` disabled for `import std;` #122

Job	Run time
std::format none C++20 Clang-18 Release	6m 28s
std::format none C++20 Clang-18 Debug	6m 23s
std::format none C++23 Clang-18 Release	2m 3s
std::format none C++23 Clang-18 Debug	1m 44s
std::format gsl-lite C++20 Clang-18 Release	6m 40s
std::format gsl-lite C++20 Clang-18 Debug	6m 17s
std::format gsl-lite C++23 Clang-18 Release	1m 46s
std::format gsl-lite C++23 Clang-18 Debug	1m 39s
std::format ms-gsl C++20 Clang-18 Release	6m 36s
std::format ms-gsl C++20 Clang-18 Debug	6m 18s
std::format ms-gsl C++23 Clang-18 Release	1m 59s
std::format ms-gsl C++23 Clang-18 Debug	1m 42s
fmtlib none C++20 Clang-18 Release	6m 41s
fmtlib none C++20 Clang-18 Debug	6m 12s
fmtlib none C++23 Clang-18 Release	1m 50s
fmtlib none C++23 Clang-18 Debug	1m 45s
fmtlib gsl-lite C++20 Clang-18 Release	6m 37s
fmtlib gsl-lite C++20 Clang-18 Debug	6m 23s
fmtlib gsl-lite C++23 Clang-18 Release	1m 52s
fmtlib gsl-lite C++23 Clang-18 Debug	1m 42s
fmtlib ms-gsl C++20 Clang-18 Release	6m 44s
fmtlib ms-gsl C++20 Clang-18 Debug	6m 10s
fmtlib ms-gsl C++23 Clang-18 Release	1m 52s
fmtlib ms-gsl C++23 Clang-18 Debug	1m 47s
	1h 39m 10s

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