Create doc links for references to interface methods,
such as "[Context.Err]".
This does not attempt to handle embedded interfaces:
The linked-to method must be declared within the named type.
Fixes #54033
Change-Id: I4d7a132affe682c85958ca785bcc96571404e6c1
Reviewed-on: https://go-review.googlesource.com/c/go/+/687395 Reviewed-by: Robert Findley <rfindley@google.com>
Auto-Submit: Damien Neil <dneil@google.com> Reviewed-by: Sean Liao <sean@liao.dev>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>