[libfuzzer] Make requested changes to docs

Bug: 901836
Change-Id: I086972b916d5b46d497a4b57ae60f64627d25551
Reviewed-on: https://chromium-review.googlesource.com/c/1321569
Reviewed-by: Bruce Dawson <brucedawson@chromium.org>
Reviewed-by: Max Moroz <mmoroz@chromium.org>
Commit-Queue: Jonathan Metzman <metzman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#605881}
1 file changed