[Code Reviews Docs] Update TBR policy for mechanical changes

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

[email protected]

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