Function def_list_item_definition_fn 

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

P Widget function that converts DefListItemDefinitionArgs to widgets.

Sets the DEF_LIST_ITEM_DEFINITION_FN_VAR.