Fix bug 32543

Fix bug 32543

Store the region and orig line into the *Occur* header line.
Retrieve this information in `occur-revert-function'.
* lisp/replace.el (occur--parse-occur-buffer): New defun.
(occur-revert-function): Use it.
(occur-engine): Store region and original position as text properties
into the *Occur* header line.
* lisp/replace.el (occur-engine): Add sensible default values for
(occur--orig-line and nlines.