Introduce Override Layout Behavior API

[thecoolwinter]

Description

Note

This is a draft temporarily, until we know the API is flexible enough to implement something like CodeEditApp/CodeEditSourceEditor#33.

Introduces an API to override how text is laid out by the layout manager. An API consumer can implement an object conforming to the TextLayoutManagerRenderDelegate protocol to provide custom behavior.

Introduces tests for new APIs.

Related Issues

• ✨ Minimap CodeEditSourceEditor#33

Checklist

• I read and understood the contributing guide as well as the code of conduct
• The issues this PR addresses are related to each other
• My changes generate no new warnings
• My code builds and runs on my machine
• My changes are all related to the related issue above
• I documented my code

Screenshots