Use Python 3 instead of 3.0.
diff --git a/Doc/library/warnings.rst b/Doc/library/warnings.rst
index c74d902..0545dbe 100644
--- a/Doc/library/warnings.rst
+++ b/Doc/library/warnings.rst
@@ -419,7 +419,7 @@
 
     .. note::
 
-        In Python 3.0, the arguments to the constructor for
+        In Python 3, the arguments to the constructor for
         :class:`catch_warnings` are keyword-only arguments.
 
     .. versionadded:: 2.6