roll: third_party/pigweed pw_containers: Fix incorrect comments

pw::IntrusiveMap and pw::IntrusiveMultiMap landed with stale comments to
avoid using the now non-existent GenericIntrusiveMap type. These lines
are confusing and incorrect, and have been removed.

Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/236992
Presubmit-Verified: CQ Bot Account <pigweed-scoped@luci-project-accounts.iam.gserviceaccount.com>
Original-Revision: dfbb287c4944f93ef48024e1e756db62f199ac44

Rolled-Repo: https://pigweed.googlesource.com/pigweed/pigweed
Rolled-Commits: fd5c648a333b9e..dfbb287c4944f9
Roller-URL: https://ci.chromium.org/b/8736315075952270049
GitWatcher: ignore
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: I7df2de1ed5b299d085e54680d2d19ff43b64af36
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/examples/+/236770
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/third_party/pigweed b/third_party/pigweed
index fd5c648..dfbb287 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit fd5c648a333b9ea5b74a72b7324b8ea44535ed3a
+Subproject commit dfbb287c4944f93ef48024e1e756db62f199ac44