version: mark some implementation details as protected

Library/Homebrew/version.rb

@@ -1,8 +1,6 @@
 class VersionElement
   include Comparable
 
-  attr_reader :elem
-
   def initialize elem
     elem = elem.to_s.downcase
     @elem = case elem
@@ -31,6 +29,10 @@ class VersionElement
   def numeric?
     @elem.is_a? Numeric
   end
+
+  protected
+
+  attr_reader :elem
 end
 
 class Version
@@ -45,10 +47,6 @@ class Version
     @detected_from_url
   end
 
-  def to_a
-    @array ||= @version.scan(/\d+|[a-zA-Z]+/).map { |e| VersionElement.new(e) }
-  end
-
   def head?
     @version == 'HEAD'
   end
@@ -98,6 +96,12 @@ class Version
     Version.new(version, true) unless version.nil?
   end
 
+  protected
+
+  def to_a
+    @array ||= @version.scan(/\d+|[a-zA-Z]+/).map { |e| VersionElement.new(e) }
+  end
+
   private
 
   def self._parse spec