Grammar fix.

Doc/whatsnew/3.4.rst

@@ -507,7 +507,7 @@ Major performance enhancements have been added:
   (Contributed by Raymond Hettinger in :issue"`18771`.)
 
 * The interpreter starts about 30% faster. A couple of measures lead to the
-  speedup. The interpreter loads less modules on startup, e.g. the :mod:`re`,
+  speedup. The interpreter loads fewer modules on startup, e.g. the :mod:`re`,
   :mod:`collections` and :mod:`locale` modules and their dependencies are no
   longer imported by default. The marshal module has been improved to load
   compiled Python code faster.