While looking at a collapsed diff, I find expanding nearby code troublesome
when I really just want to expand that whole file and not have to expand
the whole diff. There are files I care about and some I can scan the
collapsed diff or pretty much ignore.
What the diff layout really needs is a link/button/whatever at the file
boundary-header where it expands the whole file.
This would be very useful since many times diffs have multiple interested
parties that only want to look at a certain subdir or code component.
