core: Fix experimental API issue for channel state API

The earlier issue was for the feature itself, not the stabilization.

Author: ejona86

core/src/main/java/io/grpc/ConnectivityState.java

@@ -22,7 +22,7 @@
  * @see <a href="https://github.com/grpc/grpc/blob/master/doc/connectivity-semantics-and-api.md">
  * more information</a>
  */
-@ExperimentalApi("https://github.com/grpc/grpc-java/issues/28")
+@ExperimentalApi("https://github.com/grpc/grpc-java/issues/4359")
 public enum ConnectivityState {
   /**
    * The channel is trying to establish a connection and is waiting to make progress on one of the

core/src/main/java/io/grpc/ManagedChannel.java

@@ -78,7 +78,7 @@ public abstract class ManagedChannel extends Channel {
    * @throws UnsupportedOperationException if not supported by implementation
    * @since 1.1.0
    */
-  @ExperimentalApi("https://github.com/grpc/grpc-java/issues/28")
+  @ExperimentalApi("https://github.com/grpc/grpc-java/issues/4359")
   public ConnectivityState getState(boolean requestConnection) {
     throw new UnsupportedOperationException("Not implemented");
   }
@@ -101,7 +101,7 @@ public ConnectivityState getState(boolean requestConnection) {
    * @throws UnsupportedOperationException if not supported by implementation
    * @since 1.1.0
    */
-  @ExperimentalApi("https://github.com/grpc/grpc-java/issues/28")
+  @ExperimentalApi("https://github.com/grpc/grpc-java/issues/4359")
   public void notifyWhenStateChanged(ConnectivityState source, Runnable callback) {
     throw new UnsupportedOperationException("Not implemented");
   }