roll: pigweed, pw_toolchain: docs/style: Require unit tests to be in unnamed namespace

- Mention in the style guide that unit tests must be declared in an
  unnamed namespace to avoid linking issues.
- Add unnamed namespaces to tests that are missing them.

Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/231211

https://pigweed.googlesource.com/pigweed/pigweed
pigweed, pw_toolchain Rolled-Commits: 972e2d48d807a8e..b816ed566711b10
Roller-URL: https://ci.chromium.org/b/8738957237306937745
GitWatcher: ignore
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: I98fb3a0321edbd2d0447c4f13b1a4eebcf742751
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/showcase/sense/+/231138
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/MODULE.bazel b/MODULE.bazel
index 9a1385d..2325494 100644
--- a/MODULE.bazel
+++ b/MODULE.bazel
@@ -48,8 +48,8 @@
     module_name = "pigweed",
     # ROLL: Warning: this entry is automatically updated.
     # ROLL: Last updated 2024-08-21.
-    # ROLL: By https://cr-buildbucket.appspot.com/build/8738964941787707041.
-    commit = "972e2d48d807a8eb7d97767ef9afc3f55890ccee",
+    # ROLL: By https://cr-buildbucket.appspot.com/build/8738957237306937745.
+    commit = "b816ed566711b10544fc1ae2d5154e077737522c",
     remote = "https://pigweed.googlesource.com/pigweed/pigweed",
 )
 
@@ -57,8 +57,8 @@
     module_name = "pw_toolchain",
     # ROLL: Warning: this entry is automatically updated.
     # ROLL: Last updated 2024-08-21.
-    # ROLL: By https://cr-buildbucket.appspot.com/build/8738964941787707041.
-    commit = "972e2d48d807a8eb7d97767ef9afc3f55890ccee",
+    # ROLL: By https://cr-buildbucket.appspot.com/build/8738957237306937745.
+    commit = "b816ed566711b10544fc1ae2d5154e077737522c",
     remote = "https://pigweed.googlesource.com/pigweed/pigweed",
     strip_prefix = "pw_toolchain_bazel",
 )