isIn/isNotIn show incorrect text

[dalewking]

An assertion of the form

        assertThat(5).isIn(1, 2, 3, 4)

Displays an incorrect message:

expected:<[1, 2, 3, 4]> to contain:<5>

That should be more like

expected:<5> to be in:<[1, 2, 3, 4]>