Man pages matching name std::from_chars_result in section 3cxx:

std::from_chars_result.3cxx.en	debian 11 / libstdc++-10-doc
std::from_chars_result.3cxx.en	debian 12 / libstdc++-11-doc
std::from_chars_result.3cxx.en	debian 12 / libstdc++-12-doc