This PR changes the compare page to make the "..." in the between branches a clickable
link. This changes the comparison type from "..." to "..". Similarly it makes the
initial compare icon clickable to switch the head and base branches.
Signed-off-by: Andrew Thornton <art27@cantab.net>
Co-authored-by: Lauris BH <lauris@nix.lv>
Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>