Remove unused Alias#full_old_name

Author: st0012

lib/rdoc/code_object/alias.rb

@@ -59,13 +59,6 @@ def aref
     "#alias-#{type}-#{html_name}"
   end
 
-  ##
-  # Full old name including namespace
-
-  def full_old_name
-    @full_name || "#{parent.name}#{pretty_old_name}"
-  end
-
   ##
   # HTML id-friendly version of +#new_name+.