Add setfacl completions

[rominf]

Due to some reasons setfacl --modify TAB doesn't work. fish version is 2.1.0. Is this a bug or my misunderstanding of complete function?

Is there better way to add several arguments completion to several options?

[zanchey]

It's generally best to use sgrep from within completions, as grep may not behave as expected.

[rominf]

I've never heard about it. Is it portable (and preinstalled on OS X, BSD, etc.)?

It it OK now?

[zanchey]

It's defined by fish, for use in completions etc. This looks like a good start - I've merged it with a squash merge here:

To git@github.com:fish-shell/fish-shell.git
3fe1069..cfa4168 master -> master

Thanks!