Return a human-readable string such that if two ExactFloats have different
values, then their string representations are always different. This
method is useful for debugging. The string has the form "value<prec>",
where "prec" is the actual precision of the ExactFloat (e.g., "0.215<50>").
Return a human-readable string such that if two ExactFloats have different values, then their string representations are always different. This method is useful for debugging. The string has the form "value<prec>", where "prec" is the actual precision of the ExactFloat (e.g., "0.215<50>").