hash: mention encoding.BinaryAppender in Hash docs
For #62384
Change-Id: I4eeb83a4708544777815eacd6a5b6d293580c5e5
GitHub-Last-Rev:
6fdb6db4811a7b19742fec556fd5a1d5002b4e5e
GitHub-Pull-Request: golang/go#68758
Reviewed-on: https://go-review.googlesource.com/c/go/+/603405
Auto-Submit: Ian Lance Taylor <iant@google.com>
Reviewed-by: David Chase <drchase@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>