roll: third_party/pigweed pw_presubmit: Download intermediate Rust docs

When building rustdoc, ensure all intermediate build outputs are
downloaded from cache. Not all generated files are top level outputs.

This will not have a meaningful impact on build latency; the relevant
Bazel invocation takes around 27 seconds both before
(https://btx.cloud.google.com/invocations/f946997c-87ba-43ff-b6ef-bea28182ec97)
and afer
(https://btx.cloud.google.com/invocations/76496490-bb35-4efa-aa0e-2bed5c9e85b8)
this change.

Fixes: 369864378
Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/237935
Original-Revision: 88e2a70eb1e73272376557b248e459123799494d

Rolled-Repo: https://pigweed.googlesource.com/pigweed/pigweed
Rolled-Commits: 0ca182292502d0..88e2a70eb1e732
Roller-URL: https://ci.chromium.org/b/8735689915307433585
GitWatcher: ignore
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: Ic916ac1f09a2f1406a35765685a147b7724f3f85
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/experimental/+/238334
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 0ca1822..88e2a70 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit 0ca182292502d0d130b318b3c06fc15908f48346
+Subproject commit 88e2a70eb1e73272376557b248e459123799494d