[roll third_party/pigweed] pw_rpc: Fix up missing Call state_ documentation

Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/149064

https://pigweed.googlesource.com/pigweed/pigweed
third_party/pigweed Rolled-Commits: d6b036c2c385b89..255ab6106000d8d
Roller-URL: https://ci.chromium.org/b/8779655685466820865
GitWatcher: ignore
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: Ic486500c7e6a554fbef4bce91ec36a690176cc31
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/experimental/+/149451
Commit-Queue: Pigweed Integration Roller <pigweed-integration-roller@pigweed.google.com.iam.gserviceaccount.com>
Bot-Commit: Pigweed Integration Roller <pigweed-integration-roller@pigweed.google.com.iam.gserviceaccount.com>
diff --git a/third_party/pigweed b/third_party/pigweed
index d6b036c..255ab61 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit d6b036c2c385b8934e83d6d4d258870ccfcc1e08
+Subproject commit 255ab6106000d8d698ed61105bb40b11eecdaf6e