fix wrong path for all registries

docs/proposals/apiserver-watch.md

@@ -99,7 +99,7 @@ to implement the proposal.
 1. Since we want the watch in apiserver to be optional for different resource
 types, this needs to be self-contained and hidden behind a well defined API.
 This should be a layer very close to etcd - in particular all registries:
-"pkg/registry/generic/etcd" should be built on top of it.
+"pkg/registry/generic/registry" should be built on top of it.
 We will solve it by turning tools.EtcdHelper by extracting its interface
 and treating this interface as this API - the whole watch mechanisms in
 apiserver will be hidden behind that interface.