Fix typo in thread name.

src/engine/objects/City.java

@@ -1083,7 +1083,7 @@ public class City extends AbstractWorldObject {
 
         Thread destroyCityThread = new Thread(new DestroyCityThread(this));
 
-        destroyCityThread.setName("deestroyCity:" + this.getName());
+        destroyCityThread.setName("destroyCity:" + this.getName());
         destroyCityThread.start();
     }