cmd/style: do FormulaAudit by default.

Otherwise this is just doing `rubocop` checks.

Library/Homebrew/cmd/style.rb

@@ -57,8 +57,7 @@ module Homebrew
     elsif except_cops
       options[:except_cops] = except_cops
     elsif only_cops.nil? && except_cops.nil?
-      options[:except_cops] = %w[FormulaAudit
-                                 FormulaAuditStrict]
+      options[:except_cops] = %w[FormulaAuditStrict]
     end
 
     Homebrew.failed = !Style.check_style_and_print(target, options)