Fix comment in Jenkinsfile

Author: djherbis

Jenkinsfile

@@ -238,7 +238,7 @@ pipeline {
 
           gcloud container images add-tag gcr.io/kaggle-images/python:${PRETEST_TAG} gcr.io/kaggle-images/python:${STAGING_TAG}
           gcloud container images add-tag gcr.io/kaggle-private-byod/python:${PRETEST_TAG} gcr.io/kaggle-private-byod/python:${STAGING_TAG}
-          // NOTE(b/336842777): TPUVM images are tested on an actual TPU VM outside this pipeline, so they are not auto-promoted to :staging tag.
+          # NOTE(b/336842777): TPUVM images are tested on an actual TPU VM outside this pipeline, so they are not auto-promoted to :staging tag.
         '''
       }
     }