Set parent of nodes set using Element#inner_text=

This ensures that any text nodes created using Element#inner_text= have their
parent node set correctly.

lib/oga/xml/element.rb

@@ -213,7 +213,7 @@ module Oga
       #
       def inner_text=(text)
         text_node = XML::Text.new(:text => text)
-        @children = NodeSet.new([text_node])
+        @children = NodeSet.new([text_node], self)
       end
 
       ##

spec/oga/xml/element_spec.rb

@@ -268,6 +268,12 @@ describe Oga::XML::Element do
 
       @element.children.length.should == 1
     end
+
+    it 'sets the parent node of the newly inserted text node' do
+      @element.inner_text = 'foo'
+
+      @element.children[0].parent.should == @element
+    end
   end
 
   describe '#text_nodes' do