Simplify learning the syntax from the docs

[kof]

Is your feature request related to a problem? Please describe.

Currently people can't discover all syntaxes supported on a single page, because there are plugins which define syntactic extensions

Latest instance #1472

Describe the solution you'd like

Some way to discover the entire syntax, maybe we should have a combined overview that takes all syntactic extensions into account and links to the more complete plugin docs

Are you willing to implement it?
No

[kof]

As an idea, maybe we need to reorganize the navigation and content on the docs site:
Right now it's structured "by package", each package is in the menu, each package provides docs for syntax and api.

We could organise it by Syntax and by APIs, meaning

Syntax
  - Core
  - Plugin X
  - Plugin Y
API
  - Core
  - Plugin X
  - Plugin Y

When user goes to page "Syntax" they scroll the entire syntax, including all plugins, navigation would highlight the current package/plugin, but it would feel like a single document.

[kof]

We can still keep each documentation where they are right now, in the corresponding package, just render them differently, providing a better reading experience.