database/sql: fix Rows.Columns() documentation
database/sql: fix Rows.Columns() documentation

Fixes #27202

Change-Id: I83620748a81500e433795c7b2b7f13399d17f777
GitHub-Last-Rev: 64457e12ceaa408efc7f75091f1b30c35b8e5d44
GitHub-Pull-Request: golang/go#27472
Reviewed-on: https://go-review.googlesource.com/133057
Reviewed-by: Daniel Theophanes <14db39248b80c6688f7e9808ba5055f2e56426f3@gmail.com>

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