remove vertical text from dox

TBR=reed@google.com
NOTRY=true

Docs-Preview: https://skia.org/?cl=164618
Bug: skia:
Change-Id: I088b73f0f0e5f55e3bef9b7fc2211dab6e52bf97
Reviewed-on: https://skia-review.googlesource.com/c/164618
Commit-Queue: Cary Clark <caryclark@skia.org>
Auto-Submit: Cary Clark <caryclark@skia.org>
Reviewed-by: Cary Clark <caryclark@skia.org>
4 files changed