Issue #3151995 by Gábor Hojtsy, rohnjeynolds, siramsay, JD_1, maxilein,...

Issue #3151995 by Gábor Hojtsy, rohnjeynolds, siramsay, JD_1, maxilein, Arno2Mars, scrumorg, Arngrim: Log PHPStan error in project results to let people know it failed. Fix undefined errors index

src/DeprecationAnalyzer.php

@@ -276,7 +276,7 @@ final class DeprecationAnalyzer {
        $this->logger->error('PHPStan failed: %results', ['%results' => print_r($output, TRUE)]);
        $json = [
          'files' => [
-           'PHPStan failed' => 'PHP API deprecations cannot be checked. Reason: ' . $output,
+           'PHPStan failed' => 'PHP API deprecations cannot be checked. Reason: ' . print_r($output, TRUE),
            'line' => 0,
           ],
           'totals' => [