message: docs: update docs to recommend /retest repokitteh command
diff: @@ -313,9 +313,17 @@ should only be done to correct a DCO mistake.
  ## Triggering CI re-run without making changes
  -Sometimes CI test runs fail due to obvious resource problems or other issues
  -which are not related to your PR. It may be desirable to re-trigger CI without
  -making any code changes. Consider adding an alias into your `.gitconfig` file:
  +To rerun failed tasks in CI, add a comment with the the line
  +
  +```
  +/retest
  +```
  +
  +in it. This should rebuild only the failed tasks.
  +
  +Sometimes tasks will be stuck in CI and won't be marked as failed, which means
  +the above command won't work. Should this happen, pushing an empty commit should
  +re-run all the CI tasks. Consider adding an alias into your `.gitconfig` file:
  ```
  [alias]
  