Use SPDX-License-Identifiers in builtin

builtin/profiler/instrumentation.lua

@@ -1,19 +1,6 @@
---Luanti
---Copyright (C) 2016 T4im
---
---This program is free software; you can redistribute it and/or modify
---it under the terms of the GNU Lesser General Public License as published by
---the Free Software Foundation; either version 2.1 of the License, or
---(at your option) any later version.
---
---This program is distributed in the hope that it will be useful,
---but WITHOUT ANY WARRANTY; without even the implied warranty of
---MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
---GNU Lesser General Public License for more details.
---
---You should have received a copy of the GNU Lesser General Public License along
---with this program; if not, write to the Free Software Foundation, Inc.,
---51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+-- Luanti
+-- Copyright (C) 2016 T4im
+-- SPDX-License-Identifier: LGPL-2.1-or-later
 
 local format, pairs, type = string.format, pairs, type
 local core, get_current_modname = core, core.get_current_modname