completion: zsh: fix for command aliasing
A lot of people want to define aliases like gc='git commit', and zsh
allows that (when not using 'complete_aliases'), but we need to handle
services that call a function other than the main one.
With this patch we can do:
compdef _git gc=git_commit
Additionally, add compatibility for Zsh Git functions which have the
form git-commit (with dash, not underscore).
Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>