Add instruction on observing reviewer status roulette comment

- sometimes roulette suggests a reviewer and by the time
  the author of the MR is ready to review, they are busy.
  This can be due to their limit on number of reviews they
  have assigned at once. We should add some verbiage to help
  guide MR authors to observe this.

danger/roulette/Dangerfile

@@ -16,11 +16,14 @@ MARKDOWN
 
 POST_TABLE_MESSAGE = <<MARKDOWN
 
-To spread load more evenly across eligible reviewers, Danger has picked a candidate for each
-review slot, based on their timezone. Feel free to
-[override these selections](https://about.gitlab.com/handbook/engineering/projects/#gitlab)
+**Please check reviewer's status!**
+- ![available](https://gitlab-org.gitlab.io/gitlab-roulette/status-svg/_success.svg) Reviewer is available!
+- ![unavailable](https://gitlab-org.gitlab.io/gitlab-roulette/status-svg/_alert.svg) Reviewer is unavailable!
+
+Feel free to [override these selections](https://about.gitlab.com/handbook/engineering/projects/#gitlab)
 if you think someone else would be better-suited
-or use the [GitLab Review Workload Dashboard](https://gitlab-org.gitlab.io/gitlab-roulette/) to find other available reviewers.
+or use the [GitLab Review Workload Dashboard](https://gitlab-org.gitlab.io/gitlab-roulette/)
+to find other available reviewers.
 
 To read more on how to use the reviewer roulette, please take a look at the
 [Engineering workflow](https://about.gitlab.com/handbook/engineering/workflow/#basics)