(similar to issue #10, but for the ed format) For the ed diff format, when range of lines is a single line, the format differs from upstream. Upstream compacts range "a,a" as just "a": ```sh echo a > a echo b > b diff -e a b | head -1 # outputs "1c" ``` Whereas this implementation doesn't compact it: ```sh cargo run -- -e a b # incorrectly outputs "1,1c" ```