RSTile: setDecorativeObject (#2967)

Co-authored-by: ImNo <kylian@iphone.nl>

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

@@ -38,6 +38,13 @@ public interface Tile extends TileObject
 	 */
 	DecorativeObject getDecorativeObject();
 
+	/**
+	 * Sets the object on the decorative layer of the tile.
+	 *
+	 * @param decorativeObject the decorative object
+	 */
+	void setDecorativeObject(DecorativeObject decorativeObject);
+
 	/**
 	 * Gets all game objects on the tile.
 	 *