runtime: tweak wording for doc
Change-Id: Id0be4b8744ded98cd28f94d89898d8cbac0f543e
GitHub-Last-Rev:
e8a610e10a6403ad2e6daf99d461a3e539a3630d
GitHub-Pull-Request: golang/go#76197
Reviewed-on: https://go-review.googlesource.com/c/go/+/718420
Reviewed-by: Keith Randall <khr@google.com>
Auto-Submit: Keith Randall <khr@golang.org>
Reviewed-by: Michael Pratt <mpratt@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Keith Randall <khr@golang.org>