023 init in pipeline

// TEST: kernel:init used as a step in a pipeline, not top-level

~import "$std/kernel"
~import "$std/io"

~std.kernel:shape(Body) {
    mass: f64,
}

~event get_count {}
| n u32

~proc get_count {
    return .{ .n = 3 };
}

~get_count()
| n _ |>
    std.kernel:init(Body) {
        { mass: 1.0 },
        { mass: 2.0 },
        { mass: 3.0 },
    }
    | kernel k |>
        std.kernel:pairwise { k.mass += k.other.mass }

~std.io:print.ln("done")