runtime/debug: document ParseBuildInfo and (*BuildInfo).String
For #51026
Fixes #69971
Change-Id: I47f2938d20cbe9462bf738a506baedad4a7006c3
Reviewed-on: https://go-review.googlesource.com/c/go/+/621837 Reviewed-by: Dmitri Shuralyov <dmitshur@google.com> Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
Auto-Submit: Ian Lance Taylor <iant@google.com> Reviewed-by: Ian Lance Taylor <iant@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>