Make constexpr ceil

[phprus]

Fix for 858e528#r114625556

Broken on macOS 13.3.1
Apple clang version 14.0.3 (clang-1403.0.22.14.1)
C++20.

/.../fmt/test/compile-fp-test.cc:32: error: call to consteval function 'test_format<11UL, char, float, FMT_COMPILE_STRING>' is not a constant expression
/.../fmt/test/compile-fp-test.cc:32:27: error: call to consteval function 'test_format<11UL, char, float, FMT_COMPILE_STRING>' is not a constant expression
  EXPECT_EQ("392.500000", test_format<11>(FMT_COMPILE("{0:f}"), 392.5f));
                          ^
/.../fmt/include/fmt/format.h:3351:9: note: non-constexpr function 'ceil' cannot be used in a constant expression
        std::ceil((f.e + count_digits<1>(f.f) - 1) * inv_log2_10 - 1e-10));

std::ceil is constexpr since C++23 (https://en.cppreference.com/w/cpp/numeric/math/ceil)

This is not a compiler bug. This is unimplemented feature in clang and msvs. Only gcc support it.
https://en.cppreference.com/w/cpp/compiler_support

[vitaut]

Thanks for the PR!

[phprus]

@vitaut
Done.

[vitaut]

Thanks!