[warning] Correct some details in the warning documentation
[warning] Correct some details in the warning documentation

R=iannucci

Change-Id: Id89e3d575e0d9bef6ec1f2473aa2785c4bf08e0f
Reviewed-on: https://chromium-review.googlesource.com/c/infra/luci/recipes-py/+/2438952
Commit-Queue: Robbie Iannucci <40f3d43a28ebae3cb819288542e1c84d73d962d5@chromium.org>
Reviewed-by: Robbie Iannucci <40f3d43a28ebae3cb819288542e1c84d73d962d5@chromium.org>
Auto-Submit: Yiwei Zhang <50b2a565e2e78c292794832469a30ce5abc9959c@google.com>

luci/recipes-py,luci/recipes-py