[roll third_party/pigweed] pw_toolchain_bazel: Fix naming in docs

Changes llvm_toolchain -> linux_clang_toolchain

Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/184753

https://pigweed.googlesource.com/pigweed/pigweed
third_party/pigweed Rolled-Commits: 0abcebab4ca0a87..27d106436209174
Roller-URL: https://ci.chromium.org/b/8761896291167230465
GitWatcher: ignore
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: I1a6fddfbb09fb4b31bab99b5aa042278e645022d
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/experimental/+/184792
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 0abceba..27d1064 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit 0abcebab4ca0a8795a19ca87a4f41f434c69f250
+Subproject commit 27d1064362091746e088960202842eaec0fa279d