[roll third_party/pigweed] docs: Discuss fuzzing in Automated Analysis

Tested by building the docs locally and viewing them in the browser.
The module docs links (module-pw_fuzzer) don't work, but pre-existing
links to module docs also don't work locally, so that doesn't point to
an issue with this change. Filed pwbug/558 to track that.

Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/68980

https://pigweed.googlesource.com/pigweed/pigweed
third_party/pigweed Rolled-Commits: a5b131c5213b76f..74b888156b98d13
Roller-URL: https://ci.chromium.org/b/8830453864689412385
Cq-Cl-Tag: roller-builder:pigweed-sample-project-roller
Cq-Cl-Tag: roller-bid:8830453864689412385
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: I70ef9bd2de0afed72571d22bc0dc6a906083b609
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/sample_project/+/69081
Bot-Commit: Pigweed Integration Roller <pigweed-integration-roller@pigweed.google.com.iam.gserviceaccount.com>
Commit-Queue: Pigweed Integration Roller <pigweed-integration-roller@pigweed.google.com.iam.gserviceaccount.com>
diff --git a/third_party/pigweed b/third_party/pigweed
index a5b131c..74b8881 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit a5b131c5213b76fa819e1e4475e901a457fafc2f
+Subproject commit 74b888156b98d139781dbaf4a21a7e0c5bc8431d