There are still methods and variables with the word "folder" in the
name, but at least user-facing messages and warnings should use the
correct terminology.
Signed-off-by: Jack Nagel <jacknagel@gmail.com>
`rack` is a commonly used alias for `formula.prefix.parent`---so common that it
gets defined and used quite a bit. This patch makes `rack` an official method
of the `Formula` class.
It was just confusing, and since the `brew upgrade` refactor this makes more sense too.
Shame it still downloads in there etc. but whatever. Homebrew 2 will fix!
