fix(menus): sort pages and sections by default order

[james-d-elliott]

This restores the default hugo sorting behaviour.

Fixes #781

Summary

This restores the default sorting behavior of sections. It will require that users using the auto menus include a weight in the _index.md of each sub-section.

Basic example

Motivation

See #781 (comment)

Checks

• Read Create a Pull Request
• Supports all screen sizes (if relevant)
• Supports both light and dark mode (if relevant)
• Passes npm run test