net/http: document io.Seeker requirement for fs.FS arguments
Using the same wording as http.FS, even though it's not strictly
required if a content type can be determined by file extension.
Fixes #66877
Updates #44553
Change-Id: I7b70c10909bdd289a57d1998a565262b8aaf2dd2
Reviewed-on: https://go-review.googlesource.com/c/go/+/597977 Reviewed-by: Damien Neil <dneil@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>
Commit-Queue: 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>