[roll third_party/pigweed] docs: enable a bunch of missing docs

Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/40440

third_party/pigweed Rolled-Commits: 47941cc13a18e5a..a25df5fad6f35ad
Roller-URL: https://ci.chromium.org/b/8850093879559268304
Cq-Cl-Tag: roller-builder:pigweed-experimental-roller
Cq-Cl-Tag: roller-bid:8850093879559268304
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: Ia0f02fadf79a1354a4844f455d22f687fccc4596
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/experimental/+/40700
Reviewed-by: Pigweed Integration Roller <pigweed-integration-roller@pigweed.google.com.iam.gserviceaccount.com>
Commit-Queue: Pigweed Integration Roller <pigweed-integration-roller@pigweed.google.com.iam.gserviceaccount.com>
diff --git a/third_party/pigweed b/third_party/pigweed
index 47941cc..a25df5f 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit 47941cc13a18e5a20147a89f526731bfa41bbef4
+Subproject commit a25df5fad6f35ad227950577122faa10661a0df7