It can be useful to return the `RefsAt` that was announced for this
node, for example, to compare it to node events.
Change the `Handle` method to return `RefsAt` so that when it is
called it returns the local node's `RefsAt`.
Signed-off-by: Fintan Halpenny <fintan.halpenny@gmail.com>
X-Clacks-Overhead: GNU Terry Pratchett