Fix doc typo. Added missing quotes. BUG=angleproject:2297 Change-Id: Ieb6ca4ae37786f48ad3c6f5dccefef25afce23a2 Reviewed-on: https://chromium-review.googlesource.com/852636 Reviewed-by: Yuly Novikov <ynovikov@chromium.org> Commit-Queue: Frank Henigman <fjhenigman@chromium.org>