src: a/an grammar fixes
Change-Id: I179b50ae8e73677d4d408b83424afbbfe6aa17a1
GitHub-Last-Rev:
2e2d9c1e45556155d02db4df381b99f2d1bc5c0e
GitHub-Pull-Request: golang/go#63478
Reviewed-on: https://go-review.googlesource.com/c/go/+/534015
Auto-Submit: Dmitri Shuralyov <dmitshur@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Michael Knyszek <mknyszek@google.com>