Add support for yang type descriptions

Change-Id: I1fd070fb975aa82b2d4c1aa4165c5ab0153ff49f
diff --git a/tests/example-schema.yang b/tests/example-schema.yang
index 6c546d3..0db4c4f 100644
--- a/tests/example-schema.yang
+++ b/tests/example-schema.yang
@@ -88,6 +88,16 @@
         }
     }
 
+    typedef myType {
+        type int32;
+        description "My type.";
+    }
+
+    leaf typedefedLeaf {
+        type myType;
+        description "This is a typedefed leaf.";
+    }
+
     grouping upAndDown {
         leaf up {
             type boolean;