[roll third_party/pigweed] pw_stream: Add infalible methods to Rust Cursor

Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/164271

https://pigweed.googlesource.com/pigweed/pigweed
third_party/pigweed Rolled-Commits: 8228249ec9925e1..611277cb7a8a0c5
Roller-URL: https://ci.chromium.org/b/8773217308595255873
GitWatcher: ignore
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: Ic519e5ee8aca335acfbd0fdfd62f19753363c94a
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/experimental/+/164393
Bot-Commit: Pigweed Roller <pigweed-roller@pigweed-service-accounts.iam.gserviceaccount.com>
Commit-Queue: Pigweed Roller <pigweed-roller@pigweed-service-accounts.iam.gserviceaccount.com>
diff --git a/third_party/pigweed b/third_party/pigweed
index 8228249..611277c 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit 8228249ec9925e1e17e4eda788d8da7d8f6b1535
+Subproject commit 611277cb7a8a0c5092d56a14ca6e47a8c3d33901