go/doc/comment: update TODO for isStdPkg
Even better is slices.BinarySearch, leave a TODO to update to that when possible.
Change-Id: Ie1ec75c34c0329c536725b45e520693790f0520e
GitHub-Last-Rev:
6cd811b186c95752794cead3ae747f54c2d0d0c5
GitHub-Pull-Request: golang/go#62585
Reviewed-on: https://go-review.googlesource.com/c/go/+/527341
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Reviewed-by: Robert Griesemer <gri@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>