cloudsql: fixed typo in google_sql_database_instance (#12247) (#8631)

[upstream:1e79ce7e1fd460fd68397a6706e8f5ab91bb2123]

Signed-off-by: Modular Magician <[email protected]>

Author: modular-magician

.changelog/12247.txt

@@ -0,0 +1,3 @@
+```release-note:none
+
+```

website/docs/r/sql_database_instance.html.markdown

@@ -525,7 +525,7 @@ exported:
 * `connection_name` - The connection name of the instance to be used in
 connection strings. For example, when connecting with [Cloud SQL Proxy](https://cloud.google.com/sql/docs/mysql/connect-admin-proxy).
 
-* `dsn_name` - The DNS name of the instance. See [Connect to an instance using Private Service Connect](https://cloud.google.com/sql/docs/mysql/configure-private-service-connect#view-summary-information-cloud-sql-instances-psc-enabled) for more details.
+* `dns_name` - The DNS name of the instance. See [Connect to an instance using Private Service Connect](https://cloud.google.com/sql/docs/mysql/configure-private-service-connect#view-summary-information-cloud-sql-instances-psc-enabled) for more details.
 
 * `service_account_email_address` - The service account email address assigned to the
 instance.