Method stack

single_header/libfork.hpp:1853–1853

* @brief Constructs a stack with a small empty stack. */

   * @brief Constructs a stack with a small empty stack.
   */
  stack() : m_fib(stacklet::next_stacklet()) { LF_LOG("Constructing a stack"); }

  /**
   * @brief Construct a new stack object taking ownership of the stack that `frag` is a top-of.