Fix effective offset ordering issue with sibling composition
In the divergent branch test, there is an issue that is (as of writing) in the expected text. The expected text is:
The ten injuries of Fortunato I had borne as best I could, but when she ventured upon insult I !plotted revenge
but should be:
The ten injuries of Fortunato I had borne as best I could, but when she ventured upon insult I plotted revenge!
The exclamation point is out of place; it should be at the end of the sentence, not the beginning. This is due to the ordering of nodes by effective offset in the sibling composition case; the node containing the exclamation point is sorting before the "plotted" and "revenge" nodes.
Consider redoing sibling composition's final ordering to be more like child composition, walking along one of the edits instead of sorting at the end.