[roll third_party/pigweed] Docs: Remove nbsp characters

Replace nbsp characters with regular space characters for consistency.

Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/80080

https://pigweed.googlesource.com/pigweed/pigweed
third_party/pigweed Rolled-Commits: ddfd6e92fdd02c5..2a9778914884c9d
Roller-URL: https://ci.chromium.org/b/8824487589591657169
Cq-Cl-Tag: roller-builder:pigweed-sample-project-roller
Cq-Cl-Tag: roller-bid:8824487589591657169
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: Ia57f91a0ab79c4b84adc6ee3874cf0c5365b8aa3
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/sample_project/+/80201
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 ddfd6e9..2a97789 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit ddfd6e92fdd02c58d78411ace55cfae07a4f8586
+Subproject commit 2a9778914884c9dfe3528f9f506d8f024fdf94ad