kad-dht/README: Replicate record to closest peers without it

kad-dht/README.md

@@ -180,8 +180,9 @@ Then we loop:
 1. If we have collected `Q` or more answers, we cancel outstanding requests and
    return `best`. If there are no outstanding requests and `Pn` is empty we
    terminate early and return `best`. In either case we notify the peers holding
-   an outdated value (`Po`) of the best value we discovered, by sending
-   `PUT_VALUE(Key, best)` messages.
+   an outdated value (`Po`) of the best value we discovered, or holding no value
+   for the given key, even though being among the `k` closest peers to the key,
+   by sending `PUT_VALUE(Key, best)` messages.
 2. Pick as many peers from the candidate peers (`Pn`) as the `α` concurrency
    factor allows. Send each a `GET_VALUE(Key)` request, and mark it as _queried_
    in `Pq`.