Suggesting future cleanups with matching rules for applied edits

[Bennet-Sunder]

The goal is to suggest future cleanups after piranha cleanups are done, I understand we have an option to have matching rules but that runs on entire codebase but not the removed lines.

If we have code like so

if flag_check?
  do_flag_stuff
else
  do_other_stuff
end

piranha cleans up the code as such.

do_flag_stuff

now do_other_stuff is removed as well. For all such removed code as part of tree sitter edit it'll be nice if we can run our matching rules on these deleted nodes so we can add suggestions like do_other_stuff is removed so they can check and remove the definition as well if there are no other references.

For Edit.new.is_delete() I have managed to hack an implementation that runs a few rules to identify any future cleanups. It's easier for deletes as the entire edit is removed. However for edit's like the above where there is a replacement would it be possible to identify deleted nodes by comparing the tree before and after applying the edit so that a few rules can be run to identify scope for future cleanups.