Method rfind

include/jwt/string_view.hpp:265–268

  size_type rfind(const CharT ch, size_type pos) const noexcept;

  size_type rfind(basic_string_view sv, size_type pos = 0) const noexcept
  {
    return rfind(sv.data(), pos, sv.length());
  }

  size_type rfind(const CharT* str, size_type pos = 0) const noexcept
  {