chore: Follow Lean upstream

tests/syntax-tests/source/Lean/LICENSE.md

@@ -185,7 +185,7 @@ The `test.lean` file has been adpated from
    APPENDIX: How to apply the Apache License to your work.
 
       To apply the Apache License to your work, attach the following
-      boilerplate notice, with the fields enclosed by brackets "[]"
+      boilerplate notice, with the fields enclosed by brackets "{}"
       replaced with your own identifying information. (Don't include
       the brackets!)  The text should be enclosed in the appropriate
       comment syntax for the file format. We also recommend that a
@@ -193,7 +193,7 @@ The `test.lean` file has been adpated from
       same "printed page" as the copyright notice for easier
       identification within third-party archives.
 
-   Copyright [yyyy] [name of copyright owner]
+   Copyright 2020 Jeremy Avigad, Patrick Massot.
 
    Licensed under the Apache License, Version 2.0 (the "License");
    you may not use this file except in compliance with the License.