net: add Unwrap to *DNSError
Fixes #63116
Change-Id: Iab8c415555ab85097be6d2d133b3349c5219a23b
GitHub-Last-Rev:
8a8177b9af5509ebbaa701b06c79126aae7510a8
GitHub-Pull-Request: golang/go#63348
Reviewed-on: https://go-review.googlesource.com/c/go/+/532217
Auto-Submit: Ian Lance Taylor <iant@google.com>
Reviewed-by: Damien Neil <dneil@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Commit-Queue: Ian Lance Taylor <iant@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>