There's `#{shell_profile}` for exactly this purpose.
Yeah I know. I would respect the upstream name, even if the upstream name is `bash-conpletiom`.
(Of course there's `bash-completion`. One could argue that's not a good name.)
`zsh-completions` provides completion**s** for multiple commands and command groups. It should not be consistent with formulae that provide completion for a single command or command group.