Fix comment on SharedInformer.Run

The old wording suggested that `Run` only gets the controller started.
Changed the wording to make it clear that `Run` only returns after the
controller is stopped.

staging/src/k8s.io/client-go/tools/cache/shared_informer.go

@@ -53,7 +53,8 @@ type SharedInformer interface {
 	GetStore() Store
 	// GetController gives back a synthetic interface that "votes" to start the informer
 	GetController() Controller
-	// Run starts the shared informer, which will be stopped when stopCh is closed.
+	// Run starts and runs the shared informer, returning after it stops.
+	// The informer will be stopped when stopCh is closed.
 	Run(stopCh <-chan struct{})
 	// HasSynced returns true if the shared informer's store has synced.
 	HasSynced() bool