[Serverless]: API reference link should return a listing of APIs that are relevant to Serverless only

[ppf2]

Serverless Docs

Elasticsearch

Description

When clicking on API Reference badge:

It sends you to an API listing page that includes not only Serverless APIs so it can be confusing:

We should send the user to a filtered list showing only the APIs that are relevant to Serverless only.

Resources and additional context

https://www.elastic.co/docs/current/serverless/elasticsearch/http-apis

[georgewallace]

@lcawl thoughts on if this is possible?

[lcawl]

It is possible to add categories to the homepage per https://docs.bump.sh/help/hubs/create-and-manage-hubs/#group-by-categories
The reason we haven't done so at this time is that each API document can belong to only a single category.
So it would complicate situations like the upcoming billing API document, which will apply to both Elastic Cloud Hosted and Elastic Cloud Serverless.
I think we could, however, create "Self-managed" and "Elastic Cloud" categories if that would be useful (then revisit in the future if we get to the point where the Elasticsearch API document spans all the deployment types, for example).