Doc: Add iterator reference and anchor to range() documentation

Author: Aniketsy

Doc/library/functions.rst

@@ -1735,11 +1735,10 @@ are always available.  They are listed here in alphabetical order.
 
    Rather than being a function, :class:`range` is actually an immutable
    sequence type, as documented in :ref:`typesseq-range` and :ref:`typesseq`.
-   
+
    The object returned by :class:`range` is an :term:`iterator` and supports iteration.
    See also :ref:`iterator` for more information about iterators and how to implement
    custom iterable classes.
-
 .. function:: repr(object)
 
    Return a string containing a printable representation of an object.  For many