[roll third_party/pigweed] pw_cpu_exception_cortex_m: Reword docs for clarity

Rewords some of the module RST docs to be more succinct.

Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/40784

third_party/pigweed Rolled-Commits: 84acca887a79b1d..11ea213414d559c
Roller-URL: https://ci.chromium.org/b/8850034208679619008
Cq-Cl-Tag: roller-builder:pigweed-experimental-roller
Cq-Cl-Tag: roller-bid:8850034208679619008
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: If472daf348fa3092356688217ea1585eaa14c3f5
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/experimental/+/40840
Reviewed-by: 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 84acca8..11ea213 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit 84acca887a79b1d934e862e58cef4ba02bf31182
+Subproject commit 11ea213414d559ca622a74f8449864106a735548