roll: third_party/pigweed docs: Introduce Bazel-based docgen

Original-Bug: 318892911
Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/237877
Presubmit-Verified: CQ Bot Account <pigweed-scoped@luci-project-accounts.iam.gserviceaccount.com>
Original-Revision: 819e758453a9b47b17f45533f1eac2eae137395a

Rolled-Repo: https://pigweed.googlesource.com/pigweed/pigweed
Rolled-Commits: 1767a9b4087e81..819e758453a9b4
Roller-URL: https://ci.chromium.org/b/8734958883465333553
GitWatcher: ignore
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: I859a454a0afae617fa3835105ac27896233d9925
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/examples/+/240292
Commit-Queue: Pigweed Roller <pigweed-roller@pigweed-service-accounts.iam.gserviceaccount.com>
Bot-Commit: Pigweed Roller <pigweed-roller@pigweed-service-accounts.iam.gserviceaccount.com>
Lint: Lint 🤖 <android-build-ayeaye@system.gserviceaccount.com>
diff --git a/third_party/pigweed b/third_party/pigweed
index 1767a9b..819e758 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit 1767a9b4087e81d1a458e70df8eaf3f3a0ff73b9
+Subproject commit 819e758453a9b47b17f45533f1eac2eae137395a