Better explain Critical severity bugs.

Bug: None
Change-Id: I9882e3338e74875a7804733b702c2fbe4d869d60
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1616977
Reviewed-by: Andrew Whalley <awhalley@chromium.org>
Commit-Queue: Chris Palmer <palmer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#663319}
1 file changed