Controls: React text node support

Currently React nodes, such as children, show a JSON object editor by default. They should show a text editor instead, in the short term. Long term, we should support JSX #11428

[monolithed]

Is there any workaround for this one?

UPD:

{
    argTypes: {
        child: {
            table: {
                type: {
                    summary: 'React.ReactNode'
                }
            },
            control: {
                type: 'select',
                options: {
                    default: [ ],
                    withChild: [
                        <SomeComponent />
                    ]
                }
            }
        }
    }
}

[ghengeveld]

Because JSX isn’t serializable (by telejson), such values cannot be used as args. As of Storybook 6.2, you can use a mapping.