Method move_alloc

include/fmt/format.h:831–834

            FMT_ENABLE_IF(std::allocator_traits<Alloc>::
                              propagate_on_container_move_assignment::value)>
  FMT_CONSTEXPR20 auto move_alloc(basic_memory_buffer& other) -> bool {
    alloc_ = std::move(other.alloc_);
    return true;
  }
  // If the allocator does not propagate then copy the data from other.
  template <typename Alloc = Allocator,
            FMT_ENABLE_IF(!std::allocator_traits<Alloc>::