Added versionadded entry for the annotate argument.

Doc/library/pickletools.rst

@@ -26,6 +26,8 @@ ordinary users of the :mod:`pickle` module probably won't find the
    a short description.  The value of *annotate* is used as a hint for
    the column where annotation should start.
 
+  .. versionadded:: 3.2 the *annotate* argument.
+
 .. function:: genops(pickle)
 
    Provides an :term:`iterator` over all of the opcodes in a pickle, returning a