Added the error coverage for country query (#8482)

* Added the error coverage for countryquery

* Update directory-country.md

Co-authored-by: Dinesh V B <dbabu@ztech.io>
Co-authored-by: Kevin Harper <keharper@users.noreply.github.com>

Author: 3 people

src/guides/v2.3/graphql/queries/directory-country.md

@@ -112,3 +112,10 @@ The query returns a single `Country` object.
 
 *  [countries query]({{page.baseurl}}/graphql/queries/directory-countries.html)
 *  [currency query]({{page.baseurl}}/graphql/queries/directory-currency.html)
+
+## Errors
+
+Error | Description
+--- | ---
+`Country \"id\" value should be specified"` | The Country ID value must be specified to find the mapped country.
+`The country isn't available` | There is no country mapped to the given country ID.