Improve API documentation

[villesau]

Summary

Looks like there's a massive API surface, but very minimal documentation. All the components and hooks are listed, but there's not much information about them. For example the core component, Remirror: https://remirror.io/docs/api/react-core#interface-remirrorprops and https://remirror.io/docs/api/react-core#interface-remirrorprops is not documented almost at all. Some of the props that are mentioned elsewhere in the documentation (such as editable and initialContent) are lacking from the component specific docs. which makes it pretty hard to understand what is the actual api surface of the component, and what possibilities it actually offers. I believe this might block people from getting started with the editor as it makes getting your head around it pretty hard.

[satokenta940]

You might want to try Apidog for generating documents. Its user interface is designed to be intuitive, making it easy for newcomers to understand and get started, which is a significant advantage.