Docs - add documentation for using multiple queries in a template

[jasonbahl]

Currently I don't see any documentation about using multiple queries in a template, which is a pretty significant feature when sites begin to scale beyond simple templates.

I use this feature here, for example:

https://github.com/wp-graphql/acf.wpgraphql.com/blob/main/wp-templates/single-field_type.js#L163-L171

This allows me to have multiple root level queries that I can re-use. i.e. a Menu Query that is used on basically every template, and then specific template queries for the content of that specific Page, Post, User, etc.

The docs should be updated to include mention of this. Whether it's in the getting started guide or somewhere else, it should be discussed.

[Fran-A-Dev]

Thanks for the feedback @jasonbahl , I will add this to a to-do and PR