org-element: Minor fix

* contrib/lisp/org-element.el (org-element-line-break-interpreter):
  Add forgotten characters from previous commit.

contrib/lisp/org-element.el

@@ -1887,7 +1887,7 @@ Assume point is at the beginning of the line break."
 (defun org-element-line-break-interpreter (line-break contents)
   "Interpret LINE-BREAK object as Org syntax.
 CONTENTS is nil."
-  "\n")
+  "\\\\\n")
 
 (defun org-element-line-break-successor (limit)
   "Search for the next statistics cookie and return position.