If the list does not have an item at @position or
%GTK_INVALID_LIST_POSITION is given, the behavior depends on the
value of the [property@Gtk.SingleSelection:autoselect] property:
If it is set, no change will occur and the old item will stay
selected. If it is unset, the selection will be unset and no item
will be selected.
Selects the item at the given position.
If the list does not have an item at @position or %GTK_INVALID_LIST_POSITION is given, the behavior depends on the value of the [property@Gtk.SingleSelection:autoselect] property: If it is set, no change will occur and the old item will stay selected. If it is unset, the selection will be unset and no item will be selected.