Add a blank line between `brew cask info` output for multiple casks

- `brew info` adds a blank line between info output for multiple
  formulae. This replicates that display for `brew cask info`, as
  requested in Issue 6126.

Library/Homebrew/cask/cmd/info.rb

@@ -17,7 +17,8 @@ module Cask
         if json == "v1"
           puts JSON.generate(casks.map(&:to_h))
         else
-          casks.each do |cask|
+          casks.each_with_index do |cask, i|
+            puts unless i.zero?
             odebug "Getting info for Cask #{cask}"
             self.class.info(cask)
           end

Library/Homebrew/test/cask/cmd/info_spec.rb

@@ -48,6 +48,7 @@ describe Cask::Cmd::Info, :cask do
         None
         ==> Artifacts
         Caffeine.app (App)
+
         local-transmission: 2.61
         https://brew.sh
         Not installed