[roll third_party/pigweed] docs: Add sort by alignment to size optimizations

Document linker options to sort symbols by alignment

Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/184150

https://pigweed.googlesource.com/pigweed/pigweed
third_party/pigweed Rolled-Commits: 303f354624ee666..f5387e64b519f2b
Roller-URL: https://ci.chromium.org/b/8762356183378165777
GitWatcher: ignore
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: I6ba63083ae1ffe68bbf6f4d60363d70b967b85c7
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/experimental/+/184255
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 303f354..f5387e6 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit 303f354624ee666ecdec4b8c21b166f574baefe8
+Subproject commit f5387e64b519f2b515fa9e52f667c44ddee5e234