Add note on bug #2679853.

git-svn-id: svn://svn.code.sf.net/p/loki-lib/code/trunk@1004 7ec92016-0320-0410-acc4-a06ded1c099a

include/loki/flex/flex_string_shell.h

@@ -549,6 +549,8 @@ private:
     void InsertImpl(iterator i,
         FwdIterator s1, FwdIterator s2, std::forward_iterator_tag)
     {
+        // TODO: there is a bug in this method when the range to insert is inside the current range. See bug #2679853.
+
         Invariant checker(*this);
         (void) checker;
         const size_type pos = i - begin();