Defines Homebrew aliases.

Also adds the Homebrew-managed zsh/site-functions path into your fpath.

• brewa auto uninstalls formulae that are no longer needed.
• brewc cleans the cache.
• brewC scrubs the cache, including downloads for the latest versions.
• brewd checks your system for potential problems.
• brewe edits given formula.
• brewi shows information about given formula.
• brewI installs given formula.
• brewl lists installed formulae.
• brewL lists installed formulae that don't depend on other installed formula.
• brewo lists outdated installed formulae.
• brewr reinstalls given formula.
• brews performs a search of formula names.
• brewS manages background services with macOS' launchctl daemon manager.
• brewu updates Homebrew and all formulae.
• brewU upgrades outdated and unpinned formulae.
• brewx uninstalls a given formula.
• brewX deletes all installed versions of given formula.

• caske edits given cask.
• caski shows information about given cask.
• caskI installs given cask.
• caskl lists installed casks.
• casko lists outdated installed casks.
• caskr reinstalls given cask.
• casks performs a search of cask tokens.
• caskU upgrades given cask or all outdated casks, if none given.
• caskx uninstalls given cask.
• caskX uninstalls even if given cask does not appear to be present.
• caskz zaps all files associated with given cask.