Here the 1874 RLDS edition replaced the restrictive relative pronoun which with that. One might propose that this change was intentional since there is a prescriptive rule that does not permit the restrictive use of which. Yet the Book of Mormon is full of such usage and most instances of the restrictive which have been retained in the text, although cases of which referring to persons have typically been edited to who(m). There has never been any systematic effort in the editing of the Book of Mormon text to change restrictive which to that. For a brief discussion of this editing practice, see under 1 Nephi 13:23; for a complete discussion, see under which in volume 3. As far as the relative pronouns which and that are concerned, the critical text will in each case follow the earliest textual sources (thus which here in Alma 22:16).
Summary: Maintain in Alma 22:16 the restrictive use of the relative pronoun which, the reading of the earliest textual sources; restrictive which is very frequent in both the original and the current texts of the Book of Mormon.