Use “[sic]”

Warning²Federal courts, Illinois courts21st and 22nd editions

A mistake left standing in quoted language is marked “[sic]”; the brackets are what show the notation is the writer’s and not the source’s own text.¹

1. 1R. 5.2(c) Mistakes in original. Tables: R. 5.2(a) Substitution of letters or words.
2. 2A warning: the form is usually wrong under the rule in note 1, and context can justify it.