use macro

Doc/lib/emailutil.tex

@@ -104,7 +104,7 @@ Optional \var{usegmt} is a flag that when \code{True}, outputs a
 date string with the timezone as an ascii string \code{GMT}, rather
 than a numeric \code{-0000}. This is needed for some protocols (such
 as HTTP). This only applies when \var{localtime} is \code{False}.
-New in Python 2.4.
+\versionadded{2.4}
 \end{funcdesc}
 
 \begin{funcdesc}{make_msgid}{\optional{idstring}}