operator: insert

    description:
        insert[char, k] ket
        insert, one of three edit distance operators
        see: https://en.wikipedia.org/wiki/Edit_distance

    examples:
        insert["g", 6] insert["i", 4] delete["e", 4] insert["s", 0] delete["k", 0] |kitten>
            |sitting>

    see also:
        delete, substitute