Method on_align

extlibs/fmt/include/fmt/format.h:2082–2082

      : specs_(other.specs_) {}

  FMT_CONSTEXPR void on_align(align_t align) { specs_.align = align; }
  FMT_CONSTEXPR void on_fill(basic_string_view<Char> fill) {
    specs_.fill = fill;
  }