📝 Improve Dependency Injection docs

[jankoenig]

Proposed Changes

This PR adds a few more notes relevant to dependency injection and the breaking change about options: UnknownObject | undefined that was introduced.

Types of Changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist

• My code follows the code style of this project
• My change requires a change to the documentation
• I have updated the documentation accordingly
• I have added tests to cover my changes
• All new and existing tests passed