[2206] Update comments

src/lib/datasrc/memory/zone_table_segment.h

@@ -40,7 +40,7 @@ public:
         return (table.get());
     }
 
-    /// \brief const version of getTable().
+    /// \brief const version of \c getTable().
     const ZoneTable* getTable() const {
         return (getTable());
     }

src/lib/datasrc/memory/zone_table_segment_local.h

@@ -46,6 +46,8 @@ public:
     /// \brief Return the ZoneTableHeader for the local zone table
     /// segment implementation.
     ///
+    /// NOTE: This method will never return \c NULL.
+    ///
     /// \return Returns the ZoneTableHeader for this zone table segment.
     virtual ZoneTableHeader* getHeader();