Adding an epilogue at the end of an unpublished decision that affirmed a 20-year prison sentence, Justice Robert J. Steigmann repeated his sharp criticism of prevalent plea-bargaining practices and added something new — a proposal for amending Illinois Supreme Court Rule 402.Trenton Higgins was accused of aggravated battery of a child. During plea discussions under Rule 402(d), the trial judge reportedly said a sentence “in the low range, like 7 or 8 years,” might be appropriate.The plea conference wasn’t recorded. And …