Debug: Add station delete counter to NewGRF debug

src/table/newgrf_debug_data.h

@@ -740,6 +740,8 @@ class NIHStationStruct : public NIHelper {
 			}
 			seprintf(buffer, lastof(buffer), "  Station tiles: %u", st->station_tiles);
 			print(buffer);
+			seprintf(buffer, lastof(buffer), "  Delete counter: %u", st->delete_ctr);
+			print(buffer);
 		}
 	}
 };