* lisp/org-element.el (org-element-paragraph-separate): Diary-sexp
elements can separate paragraphs.
(org-element-all-elements): Install new `diary-sexp' type.
(org-element--current-element): Recognize new `diary-sexp' elements.
(org-element-diary-sexp-parser, org-element-diary-sexp-interpreter):
New functions.
* testing/lisp/test-org-element.el: Add tests.