Add comment about symlinked directories

test/test_site.rb

@@ -157,6 +157,7 @@ class TestSite < Test::Unit::TestCase
     should "sort pages alphabetically" do
       stub.proxy(Dir).entries { |entries| entries.reverse }
       @site.process
+      # files in symlinked directories may appear twice
       sorted_pages = %w(.htaccess about.html bar.html coffeescript.coffee contacts.html deal.with.dots.html foo.md index.html index.html main.scss main.scss properties.html sitemap.xml symlinked-file)
       assert_equal sorted_pages, @site.pages.map(&:name)
     end