Update a link on the current page.

def updateLink(page, lnk):
    """ Update a link on the current page. """
    CheckParent(page)
    annot = getLinkText(page, lnk)
    if annot == "":
        raise ValueError("link kind not supported")

    page.parent._updateObject(lnk["xref"], annot, page = page) 
    return