documentation: corrections to PDF docs

NOTRY=true
Change-Id: Ib3a1ca0111c9fa2ed34021420c410f816e196274
Reviewed-on: https://skia-review.googlesource.com/6820
Reviewed-by: Hal Canary <halcanary@google.com>
Commit-Queue: Hal Canary <halcanary@google.com>
1 file changed