Add a new edge kind - ParentIterative

[ketkarameya]

Earlier we had Parent and this is how it was processed:

for rule in graph.outgoing(current_rule, PARENT):
   for ancestor in context(current_location):
       Edit edit = get_edit(rule, ancestor)
       if edit : 
          return edit 

For ParentIterative we do something subtly different. We loop over the ancestors in the outer most loop:
And its processed something like :

   for ancestor in context(current_location):
       for rule in graph.outgoing(current_rule, PARENT_ITERATIVE):
         Edit edit = get_edit(rule, ancestor)
         if edit : 
          return edit 

Why suffix iterative? I thought its keeping to iterative-deepening idea from DFS.
I am open to other names.
But this pattern makes it easy to transform builder patterns (As required by Scala upgrade folks)

[lazaroclapp]

Minor nits below, plus the offline request to add the negative test case, but otherwise this LGTM!

[lazaroclapp]

Are this extra empty lines intentional?

[lazaroclapp]

Minor nit: but let's make the spacing between rules consistently, either one or two empty lines, but not a mix of the two unless it implies a particular grouping.

[lazaroclapp]

Suggested change

	// Scope level is not "Parent" or "Global"
	// Scope level is not "Parent", "Parent Iterative", or "Global"

[lazaroclapp]

Just to confirm, we are intentionally getting rid of this debug log line entirely, right?