Function list_item_bullet_fn 

pub fn list_item_bullet_fn(
    child: impl IntoUiNode,
    wgt_fn: impl IntoVar<WidgetFn<ListItemBulletFnArgs>>,
) -> UiNode

P Widget function that converts ListItemBulletFnArgs to widgets.

Sets the LIST_ITEM_BULLET_FN_VAR.