Bump to 3.9.0a0

Doc/tutorial/interpreter.rst

@@ -10,13 +10,13 @@ Using the Python Interpreter
 Invoking the Interpreter
 ========================
 
-The Python interpreter is usually installed as :file:`/usr/local/bin/python3.8`
+The Python interpreter is usually installed as :file:`/usr/local/bin/python3.9`
 on those machines where it is available; putting :file:`/usr/local/bin` in your
 Unix shell's search path makes it possible to start it by typing the command:
 
 .. code-block:: text
 
-   python3.8
+   python3.9
 
 to the shell. [#]_ Since the choice of the directory where the interpreter lives
 is an installation option, other places are possible; check with your local
@@ -98,8 +98,8 @@ before printing the first prompt:
 
 .. code-block:: shell-session
 
-   $ python3.8
-   Python 3.8 (default, Sep 16 2015, 09:25:04)
+   $ python3.9
+   Python 3.9 (default, June 4 2019, 09:25:04)
    [GCC 4.8.2] on linux
    Type "help", "copyright", "credits" or "license" for more information.
    >>>

Doc/tutorial/stdlib.rst

@@ -15,7 +15,7 @@ operating system::
 
    >>> import os
    >>> os.getcwd()      # Return the current working directory
-   'C:\\Python38'
+   'C:\\Python39'
    >>> 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

@@ -278,7 +278,7 @@ applications include caching objects that are expensive to create::
    Traceback (most recent call last):
      File "<stdin>", line 1, in <module>
        d['primary']                # entry was automatically removed
-     File "C:/python38/lib/weakref.py", line 46, in __getitem__
+     File "C:/python39/lib/weakref.py", line 46, in __getitem__
        o = self.data[key]()
    KeyError: 'primary'