ZSH, Nix, and completions

TIL that ZSH completions that come with Nix packages end up in ~/.nix-profile/share/zsh/vendor-completions/ and that folder is not added to $FPATH by the init script that comes with Nix.

After modifying the bit in ~/.zshenv it now looks like this

if [[ -f ~/.nix-profile/etc/profile.d/nix.sh ]]; then
    source ~/.nix-profile/etc/profile.d/nix.sh
    export fpath=(~/.nix-profile/share/zsh/vendor-completions ${fpath})
fi