Close peerstore and document Host Close (#1037)

* close peerstore and docs change

* update docs

libp2p.go

@@ -52,7 +52,7 @@ func ChainOptions(opts ...Option) Option {
 // - If no peerstore is provided, the host is initialized with an empty
 // peerstore.
 //
-// Canceling the passed context will stop the returned libp2p node.
+// To stop/shutdown the returned libp2p node, the user needs to cancel the passed context and call `Close` on the returned Host.
 func New(ctx context.Context, opts ...Option) (host.Host, error) {
 	return NewWithoutDefaults(ctx, append(opts, FallbackDefaults)...)
 }

p2p/host/basic/basic_host.go

@@ -1007,6 +1007,10 @@ func (h *BasicHost) Close() error {
 		_ = h.emitters.evtLocalAddrsUpdated.Close()
 		h.Network().Close()
 
+		if h.Peerstore() != nil {
+			h.Peerstore().Close()
+		}
+
 		h.refCount.Wait()
 	})