[roll third_party/pigweed] pw_software_update: Improve help strings

Testing: Changes are help-string only, but unit tests still pass
Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/61782

https://pigweed.googlesource.com/pigweed/pigweed
third_party/pigweed Rolled-Commits: e485396bb16b735..e0b03f5a2179d41
Roller-URL: https://ci.chromium.org/b/8835438544144987297
Cq-Cl-Tag: roller-builder:pigweed-experimental-roller
Cq-Cl-Tag: roller-bid:8835438544144987297
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: I4787f090a358257f88851aaacebc79d595438315
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/experimental/+/61765
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 e485396..e0b03f5 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit e485396bb16b735b0c6c227fe64e1e0c551143b6
+Subproject commit e0b03f5a2179d41753e21680aa990d77a732bc72