Fix the INTERACT disambiguation mode
Fix the INTERACT disambiguation mode

The code that processes the INDEX didn't match the format of the index
anymore, and probably was broken since the great list refactor a few
years ago. It was also much more complicated than necessary, since the
current index contains only simple Type::X entries.

So for now, make a very simple implementation that displays a list of
choices and lets the user pick one by number (or unique substring).

If any additional features are added to INDEX in the future, then this
can be replaced.

MasterDuke17/doc,tbrowder/doc,MasterDuke17/doc,tbrowder/doc,MasterDuke17/doc,tbrowder/doc,MasterDuke17/doc,tbrowder/doc