I'm a student and often find myself struggling with pseudocode to the point that I end up writing it out by hand and annotating it in a similar fashion on paper.
I agree. Answer-hubs like stackoverflow have their own place, as do Git discussions for PR's. But I'm tempted to say that there's a gap for more effective collaboration in the "in-between parts" you know, where some new contributor takes a look at the codebase and says "Huh, why is this written like this?". Instead of chat/email, the entire conversation history can be preserved adjacent to the codebase itself without being intrusive.