Commit messages starting with 'Reland ' always pass presubmit test.
Error message now shows offending lines and how to get around them.

Bug: angleproject:4683
Change-Id: If1a1ccfcf59172b10b2ca2066f3a087ff61dd4bd
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2237987
Commit-Queue: Manh Nguyen <nguyenmh@google.com>
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>