Add *,**,@ to index, as suggested by
http://farmdev.com/thoughts/24/what-does-the-def-star-variable-or-def-asterisk-parameter-syntax-do-in-python-/

The right entry type to use isn't clear; operator seems wrong, because *,**,@
aren't being used in expressions here.  I put them as 'statement'; 'syntax'
might be better.
diff --git a/Doc/reference/compound_stmts.rst b/Doc/reference/compound_stmts.rst
index be1d10e..b983a98 100644
--- a/Doc/reference/compound_stmts.rst
+++ b/Doc/reference/compound_stmts.rst
@@ -424,6 +424,9 @@
 The function definition does not execute the function body; this gets executed
 only when the function is called.
 
+.. index::
+  statement: @
+
 A function definition may be wrapped by one or more :term:`decorator` expressions.
 Decorator expressions are evaluated when the function is defined, in the scope
 that contains the function definition.  The result must be a callable, which is
@@ -464,6 +467,10 @@
        penguin.append("property of the zoo")
        return penguin
 
+.. index::
+  statement: *
+  statement: **
+
 Function call semantics are described in more detail in section :ref:`calls`. A
 function call always assigns values to all parameters mentioned in the parameter
 list, either from position arguments, from keyword arguments, or from default