+ // The labels are reversed, sort and then reversed again.
+ // Consider a list of annotations (A1, A2, C1, C2, B1, B2) where
+ // the letter signifies the span. Here we are only sorting by the
+ // span and hence, the order of the elements with the same span will
+ // not change. On reversing the ordering (|a, b| but b.cmp(a)), you get
+ // (C1, C2, B1, B2, A1, A2). All the elements with the same span are
+ // still ordered first to last, but all the elements with different
+ // spans are ordered by their spans in last to first order. Last to
+ // first order is important, because the jiggly lines and | are on
+ // the left, so the rightmost span needs to be rendered first,
+ // otherwise the lines would end up needing to go over a message.
+