Hello zsh workers!

I use perforce at work, and I've been meaning to update the p4 completion for zsh to use the newer version 2016 commands.

While working on this, I also attempted to update the existing commands and their argument descriptions.

This is my first patch to the zsh code base, and I did try to read as much about contributing as I could, but I'm sure I missed something :\

Your help submitting this patch is very much welcome :)

Thank you,
Zach Whaley