docs(license): add SPDX tags in top comment

Author: dbohdan

lsblk.lua

@@ -1,9 +1,9 @@
 #! /usr/libexec/flua
 -- List information about block devices.
---
 -- https://github.com/dbohdan/lsblk.lua
 --
--- Copyright (c) 2025 D. Bohdan
+-- SPDX-FileCopyrightText: 2025 D. Bohdan
+-- SPDX-License-Identifier: BSD-2-Clause
 --
 -- Redistribution and use in source and binary forms, with or without
 -- modification, are permitted provided that the following conditions