fix broken flatten example and update usingBookmaker

A mistake in my local script skipped running bookmaker
over some files. Also responding to latest error found
by Ravi's tool.

Docs-Preview: https://skia.org/?cl=85000
Bug: skia:6898
Change-Id: Ic76e65400850dda8f41fde19bac7e20e53d696df
Reviewed-on: https://skia-review.googlesource.com/85000
Commit-Queue: Cary Clark <caryclark@skia.org>
Reviewed-by: Cary Clark <caryclark@skia.org>
5 files changed