Markup fix

Doc/whatsnew/whatsnew25.tex

@@ -1978,7 +1978,7 @@ instead of \ctype{int} to allow processing more data
 on 64-bit machines.  Extension code may need to make 
 the same change to avoid warnings and to support 64-bit machines.
 See the earlier
-section~ref{section-353} for a discussion of this change.
+section~\ref{section-353} for a discussion of this change.
 
 \item C API: 
 The obmalloc changes mean that