roll: third_party/pigweed: docs: Add emboss to packages installed for build_docs

Allows building size for projects that use emboss.

Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/216893
Lint: Lint 🤖 <android-build-ayeaye@system.gserviceaccount.com>

https://pigweed.googlesource.com/pigweed/pigweed
third_party/pigweed Rolled-Commits: 1edcc733fe2cec8..99dfabfb6139412
Roller-URL: https://ci.chromium.org/b/8744451284723163041
GitWatcher: ignore
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: Ifa4419c0c9d9341dd6c9961e1d74fab535090442
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/examples/+/217164
Commit-Queue: Pigweed Roller <pigweed-roller@pigweed-service-accounts.iam.gserviceaccount.com>
Lint: Lint 🤖 <android-build-ayeaye@system.gserviceaccount.com>
Bot-Commit: Pigweed Roller <pigweed-roller@pigweed-service-accounts.iam.gserviceaccount.com>
diff --git a/third_party/pigweed b/third_party/pigweed
index 1edcc73..99dfabf 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit 1edcc733fe2cec8d575a19ca2e04a65b22e59ccb
+Subproject commit 99dfabfb6139412afcbc19da71a9163ccfd1fc27