Use SPDX 3.0 license identifier

SPDX released version 3 of their license list (<https://spdx.org/licenses/>),
which changed the FSF licenses to explicitly end in -only or -or-later
instead of relying on an easy to miss + symbol.

Bug: T183858
Change-Id: Id75a37eab27282ca7797fa3e6ceb92750c59477f

maintenance/ULSCompactLinksDisablePref.php

@@ -4,7 +4,7 @@
  * preference for appropriate users
  *
  * @copyright 2017 Wikimedia Language team and others; see AUTHORS.txt
- * @license GPL-2.0+
+ * @license GPL-2.0-or-later
  * @author Niklas Laxström
  * @author Amir E. Aharoni
  * Based on autodisablePref.php from the VisualEditor repository by Alex Monk