roll: third_party/pigweed 91effbe..dff9ccc (4 commits)

dff9ccc:https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/263132 docs: Treat warnings as errors in the Bazel build
2b29b9b:https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/262924 pw_cli: Move file_summary
46c7ea9:https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/260092 pw_toolchain: Support building Rust libcore from source
1b93cc9:https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/263094 docs: Use the same Doxygen version on all platforms

Rolled-Repo: https://pigweed.googlesource.com/pigweed/pigweed
Rolled-Commits: 91effbebe64f1d..dff9ccc642ac3b
Roll-Count: 1
Roller-URL: https://cr-buildbucket.appspot.com/build/8724467442098445713
GitWatcher: ignore
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: I60f35042fa711203d9efd5ff555d4278316a1b29
Reviewed-on: https://pigweed-review.googlesource.com/c/gonk/+/263232
Bot-Commit: Pigweed Roller <pigweed-roller@pigweed-service-accounts.iam.gserviceaccount.com>
Commit-Queue: 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 91effbe..dff9ccc 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit 91effbebe64f1d0ff0cf081d11a89ec41485779d
+Subproject commit dff9ccc642ac3b194c72779f69ed5682db10f626