os/signal: document behavior of SIGPIPE on non-Go thread
Fixes #56150
Change-Id: Id990783562950ba8be7ce9526b7a811625f2190a
Reviewed-on: https://go-review.googlesource.com/c/go/+/442415
Run-TryBot: Ian Lance Taylor <iant@google.com> Reviewed-by: Ian Lance Taylor <iant@google.com> Reviewed-by: Michael Pratt <mpratt@google.com>
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Auto-Submit: Ian Lance Taylor <iant@google.com>
Run-TryBot: Ian Lance Taylor <iant@golang.org>