os module doc: remove availability when useless

Remove "Availability: Unix, Windows." from os module documentation for
functions available on all platforms.

Doc/library/os.rst

@@ -312,8 +312,6 @@ process and user.
 
    Return the current process id.
 
-   Availability: Unix, Windows.
-
 
 .. function:: getppid()
 
@@ -550,8 +548,6 @@ process and user.
    On platforms where :c:func:`strerror` returns ``NULL`` when given an unknown
    error number, :exc:`ValueError` is raised.
 
-   Availability: Unix, Windows.
-
 
 .. data:: supports_bytes_environ
 
@@ -565,8 +561,6 @@ process and user.
 
    Set the current numeric umask and return the previous umask.
 
-   Availability: Unix, Windows.
-
 
 .. function:: uname()
 
@@ -657,8 +651,6 @@ as internal buffering of data.
 
    Close file descriptor *fd*.
 
-   Availability: Unix, Windows.
-
    .. note::
 
       This function is intended for low-level I/O and must be applied to a file
@@ -678,8 +670,6 @@ as internal buffering of data.
           except OSError:
               pass
 
-   Availability: Unix, Windows.
-
 
 .. function:: device_encoding(fd)
 
@@ -696,8 +686,6 @@ as internal buffering of data.
    2: stderr), the new file descriptor is :ref:`inheritable
    <fd_inheritance>`.
 
-   Availability: Unix, Windows.
-
    .. versionchanged:: 3.4
       The new file descriptor is now non-inheritable.
 
@@ -708,8 +696,6 @@ as internal buffering of data.
    The file descriptor *fd2* is :ref:`inheritable <fd_inheritance>` by default,
    or non-inheritable if *inheritable* is ``False``.
 
-   Availability: Unix, Windows.
-
    .. versionchanged:: 3.4
       Add the optional *inheritable* parameter.
 
@@ -775,8 +761,6 @@ as internal buffering of data.
 
       The :func:`.stat` function.
 
-   Availability: Unix, Windows.
-
 
 .. function:: fstatvfs(fd)
 
@@ -860,8 +844,6 @@ as internal buffering of data.
    current position; :const:`SEEK_END` or ``2`` to set it relative to the end of
    the file. Return the new cursor position in bytes, starting from the beginning.
 
-   Availability: Unix, Windows.
-
 
 .. data:: SEEK_SET
           SEEK_CUR
@@ -870,8 +852,6 @@ as internal buffering of data.
    Parameters to the :func:`lseek` function. Their values are 0, 1, and 2,
    respectively.
 
-   Availability: Unix, Windows.
-
    .. versionadded:: 3.3
       Some operating systems could support additional values, like
       :data:`os.SEEK_HOLE` or :data:`os.SEEK_DATA`.
@@ -892,8 +872,6 @@ as internal buffering of data.
    This function can support :ref:`paths relative to directory descriptors
    <dir_fd>` with the *dir_fd* parameter.
 
-   Availability: Unix, Windows.
-
    .. versionchanged:: 3.4
       The new file descriptor is now non-inheritable.
 
@@ -1079,8 +1057,6 @@ or `the MSDN <http://msdn.microsoft.com/en-us/library/z0kc8e3z.aspx>`_ on Window
    bytes read.  If the end of the file referred to by *fd* has been reached, an
    empty bytes object is returned.
 
-   Availability: Unix, Windows.
-
    .. note::
 
       This function is intended for low-level I/O and must be applied to a file
@@ -1199,8 +1175,6 @@ or `the MSDN <http://msdn.microsoft.com/en-us/library/z0kc8e3z.aspx>`_ on Window
    Write the bytestring in *str* to file descriptor *fd*. Return the number of
    bytes actually written.
 
-   Availability: Unix, Windows.
-
    .. note::
 
       This function is intended for low-level I/O and must be applied to a file
@@ -1376,8 +1350,6 @@ features:
    or not it is available using :data:`os.supports_effective_ids`.  If it is
    unavailable, using it will raise a :exc:`NotImplementedError`.
 
-   Availability: Unix, Windows.
-
    .. note::
 
       Using :func:`access` to check if a user is authorized to e.g. open a file
@@ -1430,8 +1402,6 @@ features:
    This function can support :ref:`specifying a file descriptor <path_fd>`.  The
    descriptor must refer to an opened directory, not an open file.
 
-   Availability: Unix, Windows.
-
    .. versionadded:: 3.3
       Added support for specifying *path* as a file descriptor
       on some platforms.
@@ -1493,8 +1463,6 @@ features:
    :ref:`paths relative to directory descriptors <dir_fd>` and :ref:`not
    following symlinks <follow_symlinks>`.
 
-   Availability: Unix, Windows.
-
    .. note::
 
       Although Windows supports :func:`chmod`, you can only set the file's
@@ -1545,15 +1513,11 @@ features:
 
    Return a string representing the current working directory.
 
-   Availability: Unix, Windows.
-
 
 .. function:: getcwdb()
 
    Return a bytestring representing the current working directory.
 
-   Availability: Unix, Windows.
-
 
 .. function:: lchflags(path, flags)
 
@@ -1616,8 +1580,6 @@ features:
    .. note::
       To encode ``str`` filenames to ``bytes``, use :func:`~os.fsencode`.
 
-   Availability: Unix, Windows.
-
    .. seealso::
 
       The :func:`scandir` function returns the directory entries with more
@@ -1670,8 +1632,6 @@ features:
    It is also possible to create temporary directories; see the
    :mod:`tempfile` module's :func:`tempfile.mkdtemp` function.
 
-   Availability: Unix, Windows.
-
    .. versionadded:: 3.3
       The *dir_fd* argument.
 
@@ -1830,8 +1790,6 @@ features:
 
    This function is identical to :func:`unlink`.
 
-   Availability: Unix, Windows.
-
    .. versionadded:: 3.3
       The *dir_fd* argument.
 
@@ -1865,8 +1823,6 @@ features:
 
    If you want cross-platform overwriting of the destination, use :func:`replace`.
 
-   Availability: Unix, Windows.
-
    .. versionadded:: 3.3
       The *src_dir_fd* and *dst_dir_fd* arguments.
 
@@ -1895,8 +1851,6 @@ features:
    This function can support specifying *src_dir_fd* and/or *dst_dir_fd* to
    supply :ref:`paths relative to directory descriptors <dir_fd>`.
 
-   Availability: Unix, Windows.
-
    .. versionadded:: 3.3
 
 
@@ -1909,8 +1863,6 @@ features:
    This function can support :ref:`paths relative to directory descriptors
    <dir_fd>`.
 
-   Availability: Unix, Windows.
-
    .. versionadded:: 3.3
       The *dir_fd* parameter.
 
@@ -2113,8 +2065,6 @@ features:
       >>> statinfo.st_size
       264
 
-   Availability: Unix, Windows.
-
    .. seealso::
 
       :func:`fstat` and :func:`lstat` functions.
@@ -2508,8 +2458,6 @@ features:
    name.  Please see the documentation for :func:`remove` for
    further information.
 
-   Availability: Unix, Windows.
-
    .. versionadded:: 3.3
       The *dir_fd* parameter.
 
@@ -2546,8 +2494,6 @@ features:
    :ref:`paths relative to directory descriptors <dir_fd>` and :ref:`not
    following symlinks <follow_symlinks>`.
 
-   Availability: Unix, Windows.
-
    .. versionadded:: 3.3
       Added support for specifying an open file descriptor for *path*,
       and the *dir_fd*, *follow_symlinks*, and *ns* parameters.
@@ -2799,8 +2745,6 @@ to be ignored.
    Python signal handler registered for :const:`SIGABRT` with
    :func:`signal.signal`.
 
-   Availability: Unix, Windows.
-
 
 .. function:: execl(path, arg0, arg1, ...)
               execle(path, arg0, arg1, ..., env)
@@ -2864,8 +2808,6 @@ to be ignored.
    Exit the process with status *n*, without calling cleanup handlers, flushing
    stdio buffers, etc.
 
-   Availability: Unix, Windows.
-
    .. note::
 
       The standard way to exit is ``sys.exit(n)``.  :func:`_exit` should