add explanatory comment

Author: spawnia

src/Command/ErrorFormatter/GitlabErrorFormatter.php

@@ -32,6 +32,11 @@ public function formatErrors(AnalysisResult $analysisResult, Output $output): in
 		foreach ($analysisResult->getFileSpecificErrors() as $fileSpecificError) {
 			$error = [
 				'description' => $fileSpecificError->getMessage(),
+				// This field is intended to be shown in the GitLab code quality scan widget and mentioned in the GitLab docs.
+				// However, due to a regression in GitLab, it is currently not shown - see https://gitlab.com/gitlab-org/gitlab/-/issues/578172.
+				// There is no harm in having it here, and it allows users to work around the GitLab bug by post-processing the JSON file.
+				// For example, they might prepend `check_name` to `description`, causing GitLab to show the error identifier as part of the message.
+				// TODO: remove this comment once the GitLab bug is fixed
 				'check_name' => $fileSpecificError->getIdentifier(),
 				'fingerprint' => hash(
 					'sha256',