add to the override-hints

See override-hints for a discussion of override-hints. Here we describe how to extend the list of override-hints. Note that the effects of add-override-hints events are local to the books or encapsulate events in which they reside; see add-override-hints! to avoid that restriction. Also see set-override-hints to set a new list of override-hints to it, ignoring the present list rather than adding to it.

General Forms:
(add-override-hints form)
(add-override-hints form :at-end t)
(add-override-hints form :at-end nil) ; default for :at-end
where form evaluates to a list of computed hint forms. The effect of this event is to extend the current list of override-hints by appending the result of that evaluation. The default is to append the evaluation result to the front of the current list of override-hints, but if :at-end t is specified, then the evaluation result is appended to the end of the current list.