[#CDD7E910AB63DFF4DF5E304F3C5B82E49FBC37E2]
Return a new character set which is the complement of another character set.
constexpr lut_chars operator~() const noexcept;
This function returns a new character set which contains all of the characters that are not in `*this`.
This statement declares a character set containing everything but vowels:
constexpr lut_chars not_vowels = ~lut_chars( "AEIOU" "aeiou" );
Constant.
Throws nothing.