[1431] more documentation update (forgot to commit)

src/lib/datasrc/database.h

@@ -754,7 +754,9 @@ public:
         virtual isc::dns::Name findPreviousName(const isc::dns::Name& query)
             const;
 
-        /// TBD
+	/// Look for NSEC3 for proving (non)existence of given name.
+	///
+	/// See documentation in \c Zone.
 	virtual FindNSEC3Result
         findNSEC3(const isc::dns::Name& name, bool recursive,
                   const isc::dns::ConstRRsetPtr known_encloser);

src/lib/datasrc/memory_datasrc.h

@@ -83,7 +83,9 @@ public:
                                std::vector<isc::dns::ConstRRsetPtr>& target,
                                const FindOptions options = FIND_DEFAULT);
 
-    /// TBD
+    /// Look for NSEC3 for proving (non)existence of given name.
+    ///
+    /// See documentation in \c Zone.
     virtual FindNSEC3Result
     findNSEC3(const isc::dns::Name& name, bool recursive,
               const isc::dns::ConstRRsetPtr known_encloser);