message: Add explainer for `newClient` to the search howto
diff: @@ -90,6 +90,18 @@ within your instance. The configuration options are documented in the
  The underlying functionality is using official ElasticSearch client version 7.x,
  meaning that ElasticSearch version 7 is the only one confirmed to be supported.
  +Should you need to create your own bespoke search experiences that require more
  +than just a query translator (such as faceted search or Relay pagination), you
  +can access the configuration of the search engine in order to create new elastic
  +search clients. The version of the client need not be the same as one used
  +internally by the elastic search engine plugin. For example:
  +
  +```typescript
  +import { Client } from '@elastic/elastic-search';
  +
  +const client = searchEngine.newClient(options => new Client(options));
  +```
  +
  ## Example configurations
  ### AWS
  