[BUG] Wrong "Custom Document" documentation

[rakasiwi23]

Describe the bug
Wrong "Custom Document" documentation lead to bug

To Reproduce
Steps to reproduce the behavior:

• I follow the step at Custom Document
• Reload the browser and boom I got UnhandledPromiseRejectionWarning from my terminal.

Expected behavior
Get html page with custom header title

Solution
Fix the documentation
it's not import { Document, Header, Main, Scripts } from '@airy/maleo/document';
but import { default as Document, Header, Main, Scripts, } from '@airy/maleo/document';