Docs: Use substitutions instead of manual version updates

[hugovk]

When starting a new release, the release manager has to manually edit some docs files to bump version numbers:

            'Doc/tutorial/interpreter.rst',
            'Doc/tutorial/stdlib.rst',
            'Doc/tutorial/stdlib2.rst',

• https://github.com/python/release-tools/blob/1118504e6b70a66d5df5b574bc3dbd24df7c6370/release.py#L198-L206

Similar to the technique in #115024, we can use substitutions to replace a couple of these.

Also bump some missed 3.12 -> 3.13.

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📚 Documentation preview 📚: https://cpython-previews--115416.org.readthedocs.build/

[hugovk]

I don't think we can use substitutions to replace the others?

Doc/tutorial/interpreter.rst

.. code-block:: text

   python3.13

.. code-block:: shell-session

   $ python3.13
   Python 3.13 (default, April 4 2023, 09:25:04)
   [GCC 10.2.0] on linux
   Type "help", "copyright", "credits" or "license" for more information.
   >>>

Doc/tutorial/stdlib.rst

   >>> import os
   >>> os.getcwd()      # Return the current working directory
   'C:\\Python313'
   >>> os.chdir('/server/accesslogs')   # Change current working directory
   >>> os.system('mkdir today')   # Run the command mkdir in the system shell
   0

Doc/tutorial/stdlib2.rst

   >>> import weakref, gc
   >>> class A:
   ...     def __init__(self, value):
   ...         self.value = value
   ...     def __repr__(self):
   ...         return str(self.value)
   ...
   >>> a = A(10)                   # create a reference
   >>> d = weakref.WeakValueDictionary()
   >>> d['primary'] = a            # does not create a reference
   >>> d['primary']                # fetch the object if it is still alive
   10
   >>> del a                       # remove the one reference
   >>> gc.collect()                # run garbage collection right away
   0
   >>> d['primary']                # entry was automatically removed
   Traceback (most recent call last):
     File "<stdin>", line 1, in <module>
       d['primary']                # entry was automatically removed
     File "C:/python313/lib/weakref.py", line 46, in __getitem__
       o = self.data[key]()
   KeyError: 'primary'

[erlend-aasland]

Substitutions FTW