Prefer "stringify" over "stringize".

spec/concerns/liquid_interpolatable_spec.rb

@@ -54,7 +54,7 @@ describe LiquidInterpolatable::Filters do
       }
     end
 
-    it 'should stringize a non-string operand' do
+    it 'should stringify a non-string operand' do
       @filter.to_xpath_roundtrip(nil).should == ''
       @filter.to_xpath_roundtrip(1).should == '1'
     end