docs: Update documentation and Doxygen documentation generation
diff --git a/model/ndn-content-object.h b/model/ndn-content-object.h
index 58e88a3..859543b 100644
--- a/model/ndn-content-object.h
+++ b/model/ndn-content-object.h
@@ -33,7 +33,7 @@
 namespace ndn {
 
 /**
- * @ingroup Ndn
+ * @ingroup ndn
  * @brief ContentObject header
  */
 class ContentObject : public SimpleRefCount<ContentObject>
@@ -198,7 +198,6 @@
 }
 
 /**
- * @ingroup ndn-exceptions
  * @brief Class for ContentObject parsing exception
  */
 class ContentObjectException {};