[3.15] gh-157847: Remove obsolete "Changes since Python 2.6/3.0" sections from turtle docs (GH-157846) (#157849)

(cherry picked from commit 5962fc2)

Author: StanFromIreland

Doc/library/turtle.rst

@@ -2902,49 +2902,6 @@ The demo scripts are:
 Have fun!
 
 
-Changes since Python 2.6
-========================
-
-- The methods :func:`Turtle.tracer <tracer>`, :func:`Turtle.window_width <window_width>` and
-  :func:`Turtle.window_height <window_height>` have been eliminated.
-  Methods with these names and functionality are now available only
-  as methods of :class:`Screen`. The functions derived from these remain
-  available. (In fact already in Python 2.6 these methods were merely
-  duplications of the corresponding
-  :class:`TurtleScreen`/:class:`Screen` methods.)
-
-- The method :func:`!Turtle.fill` has been eliminated.
-  The behaviour of :func:`begin_fill` and :func:`end_fill`
-  have changed slightly: now every filling process must be completed with an
-  ``end_fill()`` call.
-
-- A method :func:`Turtle.filling <filling>` has been added. It returns a boolean
-  value: ``True`` if a filling process is under way, ``False`` otherwise.
-  This behaviour corresponds to a ``fill()`` call without arguments in
-  Python 2.6.
-
-Changes since Python 3.0
-========================
-
-- The :class:`Turtle` methods :func:`shearfactor`, :func:`shapetransform` and
-  :func:`get_shapepoly` have been added. Thus the full range of
-  regular linear transforms is now available for transforming turtle shapes.
-  :func:`tiltangle` has been enhanced in functionality: it now can
-  be used to get or set the tilt angle.
-
-- The :class:`Screen` method :func:`onkeypress` has been added as a complement to
-  :func:`onkey`. As the latter binds actions to the key release event,
-  an alias: :func:`onkeyrelease` was also added for it.
-
-- The method :func:`Screen.mainloop <mainloop>` has been added,
-  so there is no longer a need to use the standalone :func:`mainloop` function
-  when working with :class:`Screen` and :class:`Turtle` objects.
-
-- Two input methods have been added: :func:`Screen.textinput <textinput>` and
-  :func:`Screen.numinput <numinput>`. These pop up input dialogs and return
-  strings and numbers respectively.
-
-
 .. doctest::
    :skipif: _tkinter is None
    :hide:

Doc/tools/removed-ids.txt

@@ -27,3 +27,7 @@ reference/expressions.html: grammar-token-python-grammar-set_display
 # Moved to a different page
 c-api/typeobj.html: c.Py_tp_base
 c-api/typeobj.html: c.Py_tp_bases
+
+# Obsolete sections in 'turtle' docs
+library/turtle.html: changes-since-python-2-6
+library/turtle.html: changes-since-python-3-0