roll: third_party/pigweed 1fd708f..6ad38d7 (3 commits)

6ad38d7:https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/299964 pw_multibuf: Add tests for code paths missing coverage
434cf8e:https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/297612 pw_kernel: Fix typo
831b160:https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/300112 pw_env_setup: Move rust toolchain to separate JSON file

Rolled-Repo: https://pigweed.googlesource.com/pigweed/pigweed
Rolled-Commits: 1fd708f82e3498..6ad38d7720ef2e
Roll-Count: 1
Roller-URL: https://cr-buildbucket.appspot.com/build/8711157441329983953
GitWatcher: ignore
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: Ib519841de77fd17dd5bc7eccdcf2fc52972ab18e
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/experimental/+/300332
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 1fd708f..6ad38d7 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit 1fd708f82e34989d87622a4a56f25eb1be19e63a
+Subproject commit 6ad38d7720ef2e75c02dd5365a0c5c13b919686f