ARGV.spec should be private

Library/Homebrew/extend/ARGV.rb

@@ -165,6 +165,8 @@ module HomebrewArgvExtension
     value 'env'
   end
 
+  private
+
   def spec
     if include?("--HEAD")
       :head
@@ -175,8 +177,6 @@ module HomebrewArgvExtension
     end
   end
 
-  private
-
   def downcased_unique_named
     # Only lowercase names, not paths or URLs
     @downcased_unique_named ||= named.map do |arg|