Added XML::Node#html? and XML::Node#xml?

The former has been moved over from XML::Text, the latter just inverts
html?.

lib/oga/xml/node.rb

@@ -163,6 +163,22 @@ module Oga
 
         node_set.insert(index, other)
       end
+
+      ##
+      # @return [TrueClass|FalseClass]
+      #
+      def html?
+        root = root_node
+
+        return root.is_a?(Document) && root.html?
+      end
+
+      ##
+      # @return [TrueClass|FalseClass]
+      #
+      def xml?
+        return !html?
+      end
     end # Element
   end # XML
 end # Oga

lib/oga/xml/text.rb

@@ -48,17 +48,6 @@ module Oga
 
         return Entities.encode(super)
       end
-
-      private
-
-      ##
-      # @return [TrueClass|FalseClass]
-      #
-      def html?
-        root = root_node
-
-        return root.is_a?(Document) && root.html?
-      end
     end # Text
   end # XML
 end # Oga