Add required lint version comment to the result-provenance fixture

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01CGhnJQpUWRRpg6H5LuWJkA

Author: ondrejmirtes

tests/PHPStan/Analyser/nsrt/result-provenance.php

@@ -1,4 +1,6 @@
-<?php declare(strict_types = 1);
+<?php // lint >= 8.0
+
+declare(strict_types = 1);
 
 namespace ResultProvenance;