Add exports for GameEngine#shutDown

Signed-off-by: Tomas Slusny <slusnucky@gmail.com>

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

@@ -51,4 +51,9 @@ public interface GameEngine
 	 * @return true if on the main thread, false otherwise
 	 */
 	boolean isClientThread();
+
+	/**
+	 * Shut downs all open connections and files in client and serializes not serialized data.
+	 */
+	void shutDown();
 }

runescape-api/src/main/java/net/runelite/rs/api/RSGameEngine.java

@@ -33,4 +33,7 @@ public interface RSGameEngine extends GameEngine, KeyFocusListener
 {
 	@Import("canvas")
 	Canvas getCanvas();
+
+	@Import("shutDown")
+	void shutDown();
 }