[Doc] Explain how to lazy load <richTextInput>

[fzaninotto]

The <RichTextInput> component depends on TipTap, which in turns depends on ProseMirror. Together, these libraries represent about 120kB of minified JavaScript. If you don't use <RichTextInput> on all your forms, you can lazy load it to reduce the size of your bundle.

To do so, replace the import:

import { RichTextInput } from 'ra-input-rich-text';

with a dynamic import:

const RichTextInput = React.lazy(() =>
    import('ra-input-rich-text').then(module => ({
        default: module.RichTextInput,
    }))
);

Once compiled, your application will load the <RichTextInput> only when needed.