[Code Reviews Docs] Update TBR policy for mechanical changes

As discussed @
https://groups.google.com/a/chromium.org/d/topic/chromium-dev/829Jj5eBhbk/discussion

R=danakj@chromium.org

Change-Id: I6a0d4a2d4d3091a48cc6c66994f4842f69aa3a87
Reviewed-on: https://chromium-review.googlesource.com/c/1340262
Commit-Queue: Gabriel Charette <gab@chromium.org>
Reviewed-by: danakj <danakj@chromium.org>
Cr-Commit-Position: refs/heads/master@{#609066}
1 file changed