Make 'copy-tree' work with records

Make 'copy-tree' work with records

* doc/lispref/lists.texi (Building Cons Cells and Lists): Document
new behavior of 'copy-tree'.
* doc/lispref/records.texi (Record Functions): Cross-reference to
lists.texi.
* etc/NEWS: Mention change.  (Bug#63509)
* lisp/emacs-lisp/shortdoc.el: Add 'copy-tree' example to vector
group.
* lisp/subr.el (copy-tree): Recurse into records as well as
vectors when optional second argument is non-nil. Rename second
argument from VECP to VECTOR-LIKE-P.
* test/lisp/subr-tests.el: Test new behavior.