api: add getOnVarTransmitListener to Widget

runelite-api/src/main/java/net/runelite/api/widgets/Widget.java

@@ -999,6 +999,13 @@ public interface Widget
 	 */
 	void setDragParent(Widget dragParent);
 
+	/**
+	 * Gets the script and arguments to be ran when one of the listened for vars changes.
+	 *
+	 * @return
+	 */
+	Object[] getOnVarTransmitListener();
+
 	/**
 	 * Sets a script to be ran when a varplayer changes
 	 *