Constant lexical_util::format::CXX20_LITERAL

pub const CXX20_LITERAL: u128 = NumberFormatBuilder::new()
    .digit_separator(num::NonZeroU8::new(b'\''))
    .case_sensitive_special(true)
    .internal_digit_separator(true)
    .build(); // 202_824_096_037_236_127_258_377_250_146_316u128

Number format for a C++20 literal floating-point number.