bug#35579: Add example of setting view-exit-action to a "function with one argument"

[積丹尼 Dan Jacobson]

I finally found an example:
(setq view-exit-action
      (lambda (buffer)
        (or (window-minibuffer-p (selected-window))
            (when (eq (window-buffer) (get-buffer "*Help*"))
              (if (one-window-p t)
                  (delete-frame)
                (delete-window))))))
So I think view-exit-action's docstring should have and example of what
they are expecting.