Product discovery for commenting on multiple lines in a diff
Design discovery for #4143
Commenting on a single line is great for simple kinds of code review feedback, but frequently a comment is actually addressing multiple lines in the diff, perhaps a portion of a logic block, a paragraph of prose or an entire function. This forces users to chose a single line to provide feedback, but the feedback may in fact be resolved with a change to a different line.
One particular challenge is that proposing a change needs an range to change multiple lines.