[roll third_party/pigweed] pw_alignment: Follow the new docs guidelines

Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/181432

https://pigweed.googlesource.com/pigweed/pigweed
third_party/pigweed Rolled-Commits: 54f1045f7e197ac..581056821fdab2f
Roller-URL: https://ci.chromium.org/b/8762952763372109169
GitWatcher: ignore
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: Ia1d2a5b7ffd4453ee84fa40ee2a297971627f582
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/experimental/+/183231
Commit-Queue: Pigweed Roller <pigweed-roller@pigweed-service-accounts.iam.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 54f1045..5810568 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit 54f1045f7e197ac2aec6226dc6f391b7cf0ad37c
+Subproject commit 581056821fdab2f257bbdc8aec67619f60c9c448