[roll] Roll third_party/pigweed docs: Add more guidance to Bazel docgen quickstart

Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/240877
Presubmit-Verified: CQ Bot Account <pigweed-scoped@luci-project-accounts.iam.gserviceaccount.com>
Original-Revision: 9fe59f4e9e23cacc4218773e108040d1632a1025
GitOrigin-RevId: 20b13789acde39c8aa42c18c3adab6ba2987a270
Change-Id: Ic50848de42b2c9647377dd67d095aa222c076129

Author: Kayce Basques

third_party/flower

@@ -504,7 +504,7 @@
              path="third_party/pigweed/src"
              remote="https://fuchsia.googlesource.com/third_party/pigweed.googlesource.com/pigweed/pigweed"
              gerrithost="https://fuchsia-review.googlesource.com"
-             revision="385019a0292797dd63f00f008efe36d52d4d698a"/>
+             revision="9fe59f4e9e23cacc4218773e108040d1632a1025"/>
     <project name="third_party/github.com/google/python_portpicker"
              gitsubmoduleof="fuchsia"
              path="third_party/python_portpicker/src"