Update spellcheck.sh

Adding copyright info per task

scripts/spellcheck.sh

@@ -1,3 +1,6 @@
+
+# Copyright (c) Meta Platforms, Inc. and affiliates.
+# This software may be used and distributed according to the terms of the Llama 2 Community License Agreement.
 # Source: https://github.com/pytorch/torchx/blob/main/scripts/spellcheck.sh
 set -ex
 sudo apt-get install aspell