This is an improvement (in my opinion) to the `brews` command that prints each leaf formula (in white), followed by its dependencies (in blue), on each line. Compared to the existing flat list of formulae, the new layout is both more compact and more informative, by differentiating leaves from dependencies at a glance.

Screenshot:
<img width="530" src="https://user-images.githubusercontent.com/1753319/130641713-b78535c9-e3f5-4dbb-80f8-22bc00e1129d.png">

BREAKING CHANGE: changes deprecated `brew cask reinstall $(...)` alias to use
`brew upgrade --cask` instead. If you don't have this command, run `brew update` to
get the latest Homebrew CLI version.
Co-authored-by: jakepez <jake@findjake.com>

add aliases for `brew pin` and `brew list --pinned`

Fixes #5623.

Add `brew cleanup` command to `bubu` alias

sorin-ionescu had some good points.

Merge completion with official brew completion. Add a helper to link official
completion into oh-my-zsh plugin (without overwriting). Add an alias to list
installed brews. Add brews to the path (in a somewhat strange way).

Reorganizing plugins so that each plugin has it's own directory now so that any plugin-specific functions can be bundled within there.

- update plugin architecture
- completion function in $ZSH/functions/brew
- plugins/brew.plugin.zsh only activates