When you know what module and functions you will need to work on for the next feature, pointing out what lines of code you will need to work with isn't hard. Making people look around where in the code they are supposed to work on shows lack of preparation, which is against what this article is about.

If you know what line of code I should change, especially on a code base I'm unfamiliar with, just tell me. If you're going to have to do as much work as I am going to have to to figure it out, then you should probably leave it up to me (given the apparent power dynamic, it's safe to assume that your time is more expensive than mine).

In complex unfamiliar code bases especially, finding the line of code can easily be 95% of the work. Not communicating that information is making the task you are asking an order of magnitude harder for no reason.

Communicating what you already know (or even just suspect) isn't micromanaging. Micromanaging would be saying something like "and if it turns out I'm wrong and you need to change some other line of code instead, you need to come ask permission".