Re-enable cancel on exiting edit_link_save()

Re-enable cancel on exiting edit_link_save()

Fixes a flaw in `edit_link_save()` in insert.js:

On exit, `edit_link_save()` correctly ends the loading state of the cancel button (i.e. the element with id `edit-close-y...`), but leaves the element disabled. This gets evident if and only if the ajax call (`action=edit_save`) returns with a `status` of `fail`, since only then the edit row with the disabled cancel button will not be faded out.