remove some copyright notices supserseded by the toplevel ones

Doc/README.txt

@@ -108,27 +108,3 @@ and we will process your request as soon as possible.
 
 If you want to help the Documentation Team, you are always welcome.  Just send
 a mail to docs@python.org.
-
-
-Copyright notice
-================
-
-The Python source is copyrighted, but you can freely use and copy it
-as long as you don't change or remove the copyright notice:
-
-----------------------------------------------------------------------
-Copyright (c) 2000-2014 Python Software Foundation.
-All rights reserved.
-
-Copyright (c) 2000 BeOpen.com.
-All rights reserved.
-
-Copyright (c) 1995-2000 Corporation for National Research Initiatives.
-All rights reserved.
-
-Copyright (c) 1991-1995 Stichting Mathematisch Centrum.
-All rights reserved.
-
-See the file "license.rst" for information on usage and redistribution
-of this file, and for a DISCLAIMER OF ALL WARRANTIES.
-----------------------------------------------------------------------

Modules/_collectionsmodule.c

@@ -3,8 +3,6 @@
 
 /* collections module implementation of a deque() datatype
    Written and maintained by Raymond D. Hettinger <python@rcn.com>
-   Copyright (c) 2004 Python Software Foundation.
-   All rights reserved.
 */
 
 /* The block length may be set to any number over 1.  Larger numbers

Modules/itertoolsmodule.c

@@ -4,8 +4,6 @@
 
 /* Itertools module written and maintained
    by Raymond D. Hettinger <python@rcn.com>
-   Copyright (c) 2003-2013 Python Software Foundation.
-   All rights reserved.
 */
 
 

Objects/setobject.c

@@ -2,9 +2,6 @@
 /* set object implementation
    Written and maintained by Raymond D. Hettinger <python@rcn.com>
    Derived from Lib/sets.py and Objects/dictobject.c.
-
-   Copyright (c) 2003-2008 Python Software Foundation.
-   All rights reserved.
 */
 
 #include "Python.h"