mininotation degradeBy operator "as a whole"

[ndr-brt]

As discussed in #742 it could be good to have another operator like ? with a non-recursive approach.

e.g. assuming the new operator defined as ??, this pattern: drawLine *[a b]??" would result in something like |ab|..|ab|ab|..|..|ab|..|ab|ab|ab|..|..|ab|..|ab