reflect: clean up unnecessary comments for rtype
For consistency, this CL cleans up unnecessary comments,
and moves these Overflow methods to exported area.
For #60427
Change-Id: I14d4ffbc3552d31c211ea1e0b7a0f7090a4a8b89
GitHub-Last-Rev:
acdc6ad51bd9ad60a34fdfa8f00a7652cbe34510
GitHub-Pull-Request: golang/go#66019
Reviewed-on: https://go-review.googlesource.com/c/go/+/567917
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>
Reviewed-by: Michael Knyszek <mknyszek@google.com>