Does not work with homebrew

[ICHx]

Hi I'm in an environment on Ubuntu Linux that also have homebrew installed.

This plugin worked with system level bash-completions but not with brews (such as linode-cli) that only have bash-completions.

I do not wish to override the lookup path, perhaps the plugin could allow additional lookup path or detect homebrew

[ICHx]

I was required to manually source the completion script after the plugin is loaded with like

emulate sh -c 'source $HOMEBREW_PREFIX/etc/bash_completion.d/linode-cli'