Added XML::Document#html?

lib/oga/xml/document.rb

@@ -77,6 +77,13 @@ module Oga
         return xml
       end
 
+      ##
+      # @return [TrueClass|FalseClass]
+      #
+      def html?
+        return type == :html
+      end
+
       ##
       # Inspects the document and its child nodes. Child nodes are indented for
       # each nesting level.

lib/oga/xml/element.rb

@@ -307,7 +307,7 @@ module Oga
         self_closing = children.empty?
         root         = root_node
 
-        if root.is_a?(Document) and root.type == :html \
+        if root.is_a?(Document) and root.html? \
         and !HTML_VOID_ELEMENTS.include?(name)
           self_closing = false
         end