kernel.cmodified to implement newline

kernel.c

@@ -118,5 +118,7 @@ void kernel_main() {
    * yet, '\n' will produce some VGA specific character instead.
    * This is normal.
    */
-  terminal_writestring("Hello, kernel World!\n");
+  for (int i = 0; i < 25; i++) {
+  terminal_writestring("Hello World!\nHello World!\n");
+  }
 }