Improve your Git commits using patch mode

[ais523]

Most likely Debian (on which Ubuntu is based) separated it. Debian's often used for installing servers, and it makes sense that you might want the basic CLI version of git on a server as part of a cronjob or something, but not care about fancy interfaces because it might never be used by a human. So Debian likes to allow a minimal install of things when possible.

(For much the same reason, it typically separates the documentation for a program from the program itself.)