Hygiene: Discourage use of $.each

Hygiene: Discourage use of $.each

Even though Array.prototype.forEach only works on arrays, and
$.each is more generic, I think it makes sense to begin discouraging
the usage of $.each now. This can be overriden by ignore lines or
by Array.prototype.forEach compatible lines. This doesn't seem too
much of an ask of engineers and helps future migrations

Bug: T200877
Change-Id: I339cff311a830699c8e32f07cec338a39870c53f