database/sql: fix comment grammar
database/sql: fix comment grammar

Change-Id: I92d8c93967c5ec57f07151affd0041f00e405057
GitHub-Last-Rev: 2dea977d938a504604aed6a9ae87986001f96acd
GitHub-Pull-Request: golang/go#30551
Reviewed-on: https://go-review.googlesource.com/c/go/+/164970
Reviewed-by: Brad Fitzpatrick <ae9783c0b0efc69cd85ab025ddd17aa44cdc4aa5@golang.org>

golang/go,CAFxX/go,cloudflare/go,akutz/go,nawawi/go,golang/go,nawawi/go,cloudflare/go,akutz/go,golang/go,josharian/go,josharian/go,josharian/go,josharian/go,cloudflare/go,nawawi/go,CAFxX/go,josharian/go,josharian/go,golang/go,akutz/go,golang/go,akutz/go,akutz/go,cloudflare/go,CAFxX/go,CAFxX/go,nawawi/go,golang/go,golang/go,CAFxX/go,akutz/go,nawawi/go,cloudflare/go,josharian/go,akutz/go,akutz/go,CAFxX/go,nawawi/go,cloudflare/go,cloudflare/go,nawawi/go,CAFxX/go,cloudflare/go,CAFxX/go,golang/go,josharian/go,nawawi/go