We were selectively requiring the tap.rb file in a few places for
performance reasons. The main method we were referencing was the
`Tap.cmd_directories` method which uses `Pathname` and the `TAP_DIRECTORY`
constant internally. `Tap.cmd_directories` is mostly used in the `Commands`
module and that is loaded very early on in the program so it made sense
to move that command to that module. To facilitate that I moved the
`TAP_DIRECTORY` constant to the top-level and renamed it to
`HOMEBREW_TAP_DIRECTORY`. It now lies in the tap_constants.rb file.
A nice bonus of this refactor is that it speeds up loading external
commands since the tap.rb file is no longer required by default in
those cases.
- Fixing the test expected output was unbelievably tedious.
- There's been debate about this setting being `false` but in
https://github.com/Homebrew/brew/pull/15136#issuecomment-1500063225
we decided that it was worth using the default since RuboCop behaviour changed
so we'd have had to do some horrible things to keep it as `false` -
https://github.com/Homebrew/brew/pull/15136#issuecomment-1500037278 -
and multiple maintainers specify the `--display-cop-names` option to
`brew style` themselves since it's clearer what's gone wrong.
