Remove duplicate word (rules)

Doc/whatsnew/whatsnew23.tex

@@ -1974,7 +1974,7 @@ removing any dependence on a system version or local installation of
 Expat.
 
 \item If you dynamically allocate type objects in your extension, you
-should be aware of a change in the rules rules relating to the
+should be aware of a change in the rules relating to the
 \member{__module__} and \member{__name__} attributes.  In summary,
 you will want to ensure the type's dictionary contains a
 \code{'__module__'} key; making the module name the part of the type