nixpkgs/zsh: add completions for programs in ~/.nix-profile

.config/nixpkgs/zsh/flake.nix

@@ -25,6 +25,8 @@
             source ${nix-zsh-completions}/share/zsh/plugins/nix/nix-zsh-completions.plugin.zsh
             fpath+=(${nix-zsh-completions}/share/zsh/site-functions)
 
+            fpath+=(~/.nix-profile/share/zsh/site-functions)
+
             autoload -U compinit && compinit
 
             source ${zsh-bd}/share/zsh-bd/bd.plugin.zsh