Couchbase (Server) Requirements: Query and Index services as prerequisites for Sync Gateway

https://docs.couchbase.com/sync-gateway/current/get-started-prepare.html#lbl-req-minim
There are descriptions about compatibility and configuration (RBC User and Bucket), but no information about cluster composition here.

I heard from James Flatter on #mobile-support channel as follows:
previously, SG used only Views for its indexing needs, which only required the Data Service. In all recent versions, it uses (by default) GSI and N1QL for that purpose, so does require Index and Query Services. If deploying on-prem, it's theoretically possible to configure it to use the old method of Views, but it's definitely not recommended and isn't something that would be possible with App Services.

As I was encouraged by him, I'd like to propose to add a clear statement about the above prerequisite to the official documentation.