roll: third_party/pigweed bb6bcba..c15953e (2 commits)

c15953e:https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/251812 Reland "docs: Build module docs with Bazel"
36e5cc3:https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/252813 pw_tokenizer: Check _pool before using it

Rolled-Repo: https://pigweed.googlesource.com/pigweed/pigweed
Rolled-Commits: bb6bcba55e7df3..c15953e4b52325
Roll-Count: 1
Roller-URL: https://cr-buildbucket.appspot.com/build/8728991678630057889
GitWatcher: ignore
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: Iae6773c1944bed46178f12246626cf611f73c9c9
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/examples/+/253255
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 bb6bcba..c15953e 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit bb6bcba55e7df334ff5b89d462bfce797130aa1d
+Subproject commit c15953e4b52325db4bba28cfa33a1fcd7bff3ad1