Fix dialyzer Shard module warning (#201)

Author: elfenlaid

lib/phoenix/tracker/shard.ex

@@ -406,7 +406,7 @@ defmodule Phoenix.Tracker.Shard do
 
   defp clock(state), do: State.clocks(state.presences)
 
-  @spec clockset_to_sync(t) :: [State.replica_name]
+  @spec clockset_to_sync(t) :: [State.name]
   defp clockset_to_sync(state) do
     my_ref = Replica.ref(state.replica)