Remove comment that no longer applies.

Doc/ext/newtypes.tex

@@ -785,6 +785,3 @@ And, a sample of its use might be something like the following:
         return NULL;
     }
 \end{verbatim}
-
-%For a reasonably extensive example, from which most of the snippits
-%above were taken, see \file{newdatatype.c} and \file{newdatatype.h}.