[roll third_party/pigweed] docs: Fix "gn args" examples which reference pw_env_setup_PACKAGE_ROOT

Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/156452

https://pigweed.googlesource.com/pigweed/pigweed
third_party/pigweed Rolled-Commits: fa54fc66949487c..376018c32f5f57b
Roller-URL: https://ci.chromium.org/b/8775210965690196849
GitWatcher: ignore
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: I87d366d59da5cd7a3999f33b3e810b57c3a68316
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/experimental/+/156752
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 fa54fc6..376018c 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit fa54fc66949487c776aca7fd9232eb91c998ad48
+Subproject commit 376018c32f5f57b809f2114dc7dff2066ba3b5a2