Documentation: fix width

NOTRY=true
Change-Id: I60861019cc19537eaff000dec15b4ecbea54e915
Reviewed-on: https://skia-review.googlesource.com/9298
Commit-Queue: Hal Canary <halcanary@google.com>
Reviewed-by: Hal Canary <halcanary@google.com>
1 file changed