Edit section links broken with h5/h6 headings
When I press "Edit this section" on "section h4.3" (that link http://demo.redmine.org/projects/test-wiki/wiki/Wiki/edit?section=4) it opens editing "h5. section h5.1".
It seems as wiki doesn't count h5 sections when show "Edit this section" but counts h5 sections when you click it to edit.
Affected versions: 1.4.4 and 2.0.3.