[Serverless]: Kibana Base URL is indicated as localhost:5601 (No guide to retrieve actual serverless Kibana URL)

[michaelsupangkat]

Serverless Docs

Kibana Serverless API

Description

In the entire API documentation (including the curl examples), Base URL still points to localhost, which could be confusing even as a placeholder. Should be replaced with a clearer placeholder value eg. <insert_kibana_url_here> and indicate where to retrieve the serverless Kibana URL

Resources and additional context

Context of this issue is for https://www.elastic.co/docs/api/doc/serverless

[lcawl]

This PR will require investigation of where users can obtain the Kibana URL. Currently only the Elasticsearch API URL is covered in https://www.elastic.co/guide/en/serverless/current/elasticsearch-connecting-to-es-serverless-endpoint.html#elasticsearch-get-started-endpoint

[lcawl]

I've created elastic/kibana#202373 to differentiate the URLs used in the Kibana and Kibana Serverless OpenAPI documents.