Support for code actions like "add missing imports" and "remove unused imports"

[wojciech-kulik]

I would love to be able to add missing imports to modules by using code actions. Even if only for basic modules like Foundation, SwiftUI, UIKit in the first stage. Also, seeing/being able to delete unused imports would be helpful as well.

Maybe this functionality already exists, but I couldn't find it. Please consider adding it 🙏

[ahoppen]

Tracked in Apple’s issue tracker as rdar://123555788