api: make IterableHashTable generic

runelite-api/src/main/java/net/runelite/api/Client.java

@@ -861,7 +861,7 @@ public interface Client extends GameEngine
 	 *
 	 * @return the map
 	 */
-	IterableHashTable getMessages();
+	IterableHashTable<MessageNode> getMessages();
 
 	/**
 	 * Gets the viewport widget.

runelite-api/src/main/java/net/runelite/api/IterableHashTable.java

@@ -24,7 +24,7 @@
  */
 package net.runelite.api;
 
-public interface IterableHashTable extends Iterable
+public interface IterableHashTable<T extends Node> extends Iterable<T>
 {
-	Node get(long hash);
+	T get(long hash);
 }