- in `brew.sh` split the `case` into those cases that take a single or
no arguments and those that take multiple arguments or handle
multiple commands. This considerably speeds up the
`brew shellenv bash` case that wasn't being handled here before.
- add `setup-ruby` to the list of commands that can be called quickly
by `brew.sh` without additional setup. This speeds up the
`brew setup-ruby` no-op case by ~10x.
- add a parameter to `setup-ruby` to avoid running Bundler if the
command doesn't need it. This makes many more cases for
`brew setup-ruby` to be no-op cases.
- Remove the (now) unused `HOMEBREW_RUBY3` check in `setup-ruby`.
- Improve argument handling in `command_path.sh` to allow it to be
used as a function in `setup-ruby.sh`.
- Add a new RuboCop to check usage of `install_bundler_gems!` is only
inside `dev-cmd` (or a few other acceptable places).
- Use new `processed_source.file_path` API in `formula_cop.rb`
This command, a bit like `install-bundler-gems`, is intended to be run
to ensure that the next invocation of `brew` will not need to try and
install Ruby or Bundler gems.
