Code review UX improvements

Description

The code reviewing UX in Gitlab is currently extremely frustrating.

Here's what Gitlab CURRENTLY does:

• I leave a comment for the MR author.
• Author replies and/or changes the code.
• The discussion goes away from the updated code, presumably because the line changed and Gitlab can't figure out where to stick the discussion now.
• The discussion is only visible on the "Discussions" tab, on a snippet of the old code (i.e. I can't see the new code, or any old code after my comment).
• To see the old code, I have to make a note of which file and line the comment was on, switch to the "changes" tab and hunt down the same file and line of code and see how the code was changed.
• To resolve the discussion, I have to go back to the discussions tab and leave a comment there. As you can imagine, this is extremely frustrating and confusing.

It would be much better if I could see a range of N lines around my comment, as well as how these changed between commits. A good place for this would be the discussions page, as I usually don't want to see the rest of the code again after I've made a first review pass and left some comments. Past that point, I only want to see the changes the new commits brought.

I realize there's no straightforward fix for what I'm asking for, and I apologize for the dearth of suggestions, but I remember code reviews being much more pleasant with Stash, so maybe there are some UX hints there. Other than that, I would think about what the workflow for a code review is, and try to find ways to help it along, as the current UX really doesn't help with that.