I've been thinking about some code annotation tool recently, where you can quickly plaster a code base with (linked) notes. This could be used to outline a new

I've been thinking about some code annotation tool recently, where you can quickly plaster a code base with (linked) notes. This could be used to outline a new feature for a junior to implement, but also when trying to understand a new code base. There's a few tools similar, but not exactly how I imagine it to be. Has anyone found a tool for the use-cases mentioned above?