Allow some docs to be turned off so they are only visible in the code.

doc-src/lib/stylesheets.rb

@@ -97,7 +97,7 @@ def mixins(item)
   comment = nil
   sass_tree.children.each do |child|
     if child.is_a?(Sass::Tree::MixinDefNode)
-      child.comment = comment
+      child.comment = comment && Sass::Tree::CommentNode.clean(comment)
       comment = nil
       mixins << child
     elsif child.is_a?(Sass::Tree::CommentNode)

doc-src/lib/stylesheets/sass_extensions.rb

@@ -150,6 +150,9 @@ module Sass
       attr_accessor :imported_filename unless method_defined? :imported_filename
     end
     class CommentNode < Node
+      def self.clean(docstring)
+        docstring.gsub(/@doc off(.*?)@doc on/m, '')
+      end
       def docstring
         ([value] + lines).join("\n")
       end