As we know, files cannot be moved across filesystems atomically. In that
case, FileUtils.mv will make a copy. But if we create the temp file in
the same directory as the target, we can avoid this and use File.rename
directly.

Additionally, the rename should be the absolute last step, so that the
original file is preserved if altering ownership and permissions fails.

This was added in d2ecfb9 / Homebrew/homebrew#12784 to fix a bug repotted in Homebrew/homebrew#12779, but
at that time we were invoking the editor via `system` rather than
`exec`.

Now we are using exec, and running it through an interactive shell seems
to cause other problems, for example, emacs does not suspend/resume
properly.

Fixes Homebrew/homebrew#32328.

Closes Homebrew/homebrew#31451.
Closes Homebrew/homebrew#32223.

Avoid problems like Homebrew/homebrew#32367.

This was added in 3a7a3619f7016c75c3e53e944221bf7f6354a63b to make the
tests pass, but this method is now stubbed out in the tests, so we can
assume $? will be non-nil.

Fixes Homebrew/homebrew#32410.

Closes Homebrew/homebrew#32394.

Long term we should probably rename the installer's "f" attribute to
"formula".

If ARGV.named.empty?, then ARGV.formulae.map(&:name) == [].

None of these subclasses share any behavior other than what is inherited
from RuntimeError, so we can just get rid of the superclass.

This class is never instantiated directly, and all subclasses
initializers have different signatures and do not rely on this.

It will cut off the beginning of any interpolated lines.

Fixes Homebrew/homebrew#32259.

Fixes Homebrew/homebrew#32234.