When running this command with multiple cursors, if one of them was at a
later position in the buffer but lying on a shallower node, it could
happen that its start could move prior to cursors that were before it
but lying on a deeper node.
This could cause the selection merging algorithm to mistakenly keep some
selections even if they overlapped. With this commit we now sort
selections prior to merging them in `Editor::select_larger_syntax_node`.
Antonio Scandurra
7c418313a7
