Add ShopPlayer#sendMessage for formatted messages

api/src/main/java/de/epiceric/shopchest/api/player/ShopPlayer.java

@@ -23,6 +23,16 @@ public interface ShopPlayer {
      */
     Player getPlayer();
 
+    /**
+     * Sends a (formatted) message to this player
+     * 
+     * @param message the message (a format string)
+     * @param args the arguments referenced by the format
+     */
+    default void sendMessage(String message, Object... args) {
+        getPlayer().sendMessage(String.format(message, args));
+    }
+
     /**
      * Gets this player's flag
      *