[roll third_party/pigweed] docs: Add CLI style guide

Original-Bug: 329532962
Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/197010

https://pigweed.googlesource.com/pigweed/pigweed
third_party/pigweed Rolled-Commits: a6d09d4aec4b9b0..2018db0bc261192
Roller-URL: https://ci.chromium.org/b/8752813679750517009
GitWatcher: ignore
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: Id85a4552d15a3f7ae5e27100bfec08c98d848c4d
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/experimental/+/198770
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 a6d09d4..2018db0 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit a6d09d4aec4b9b0c0ea6eaa0906684aab634c296
+Subproject commit 2018db0bc2611925c3dfeb05d1678d97c292cf81