org-element: Fix parsing error in `org-element-context'

org-element: Fix parsing error in `org-element-context'

* lisp/org-element.el (org-element-text-markup-successor,
  org-element-latex-or-entity-successor,
  org-element-export-snippet-successor,
  org-element-footnote-reference-successor,
  org-element-inline-babel-call-successor,
  org-element-inline-src-block-successor,
  org-element-line-break-successor, org-element-link-successor,
  org-element-plain-link-successor, org-element-macro-successor,
  org-element-radio-target-successor,
  org-element-statistics-cookie-successor,
  org-element-sub/superscript-successor,
  org-element-table-cell-successor, org-element-target-successor,
  org-element-timestamp-successor): Remove LIMIT argument.
(org-element--parse-objects, org-element--get-next-object-candidates):
Apply signature change to successors.
(org-element-context): Narrow buffer around object containers so
parsing of objects when using this function is done under the same
restrictions as in buffer parsing.
* testing/lisp/test-org-element.el: Add test.