[Plugin: Subpages Navigation] restrict levels

thanks for this plugin!

it would be great if you could add an option so we can specify how many levels lower the widget should show from the current page. ideally, it would be nice if you could also enter negative values

ex:
if levels == 1, then only immediate children are shown
if levels == -1, then only immediate parents are shown
if levels == 0, then all children are shown

https://www.ads-software.com/extend/plugins/subpage-navigation/