Document the new bug and test lines behavior of the release rollers

BUG=skia:6506
NOTRY=true
DOCS_PREVIEW= https://skia.org/?cl=13686
Change-Id: I8f38d2f87784a846ccdc4be54d0f07e0fe98f7dc

Change-Id: I8f38d2f87784a846ccdc4be54d0f07e0fe98f7dc
Reviewed-on: https://skia-review.googlesource.com/13686
Reviewed-by: Matt Sarett <msarett@google.com>
Commit-Queue: Ravi Mistry <rmistry@google.com>
1 file changed