message: Add code sample for ConfigApi access in frontend
  Per
diff: @@ -112,7 +112,16 @@ example `getString`. These will throw an error if there is no value available.
  The [ConfigApi](../reference/utility-apis/Config.md) in the frontend is a
  [UtilityApi](../api/utility-apis.md). It's accessible as usual via the
  -`configApiRef` exported from `@backstage/core-plugin-api`.
  +`configApiRef` exported from `@backstage/core-plugin-api`:
  +
  +```
  +import { useApi, configApiRef } from '@backstage/core-plugin-api';
  +...
  +const MyReactComponent = (...) => {
  + const config = useApi(configApiRef);
  + ...
  +}
  +```
  Depending on the config api in another API is slightly different though, as the
  `ConfigApi` implementation is supplied via the App itself and not instantiated
  