completion: zsh: simplify nl_append

It's exactly the same as __gitcomp_nl(), no need to duplicate code.

Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

contrib/completion/git-completion.zsh

@@ -119,10 +119,7 @@ __gitcomp_nl ()
 
 __gitcomp_nl_append ()
 {
-	emulate -L zsh
-
-	compset -P '*[=:]'
-	compadd -Q -S "${4- }" -p "${2-}" -- ${(f)1} && _ret=0
+	__gitcomp_nl "$@"
 }
 
 __gitcomp_file_direct ()