[roll third_party/pigweed] docs: Clean up remaining instances of code::

Changes the remaining instances of code:: to code-block:: to match
everywhere else.

Original-Bug: b/300317685
Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/172050

https://pigweed.googlesource.com/pigweed/pigweed
third_party/pigweed Rolled-Commits: f7d387e4036533d..418fa41be76b7a4
Roller-URL: https://ci.chromium.org/b/8769392370447973041
GitWatcher: ignore
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: Iae2c112d02ebce71c8373f5adc22039d1e34c6fa
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/experimental/+/172132
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 f7d387e..418fa41 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit f7d387e4036533d91b400f35ea7e5a18ee717875
+Subproject commit 418fa41be76b7a439d8b351025c23539d2d1591a