Removes the element named el from x if
present and keeps the information as an equally named
attribute.
util_process_copyright(x, el = "copyright")list(), to be processed.
character(1), name of the element to remove.
Defaults to "copyright" as this is the intended use
of the function.
list, with the el element removed and added
as attribute, if it is present in x. Unchanged x
otherwise.