Update formatting_windows.py

[excript]

When running Fire with PyInstaller on Windows by setting the option "console=False" in SPEC file "pyinstaller.spec" (see below) the executable dont work.

PyInstaller SPEC file

PyInstaller Spec File
exe = EXE(
    pyz,
    a.scripts,
    [],
    exclude_binaries=True,
    name='VHTools',
    debug=False,
    bootloader_ignore_signals=False,
    strip=False,
    upx=True,
    >>>    console=False,
    disable_windowed_traceback=False,
    argv_emulation=False,
    target_arch=None,
    codesign_identity=None,
    entitlements_file=None,
)

Below we have the executable message released:

Traceback (most recent call last):
  File "app.py", line 160, in <module>
    import fire
  File "<frozen importlib._bootstrap>", line 1007, in _find_and_load
  File "<frozen importlib._bootstrap>", line 986, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 680, in _load_unlocked
  File "PyInstaller\loader\pyimod02_importers.py", line 419, in exec_module
  File "fire\__init__.py", line 21, in <module>
    from fire.core import Fire
  File "<frozen importlib._bootstrap>", line 1007, in _find_and_load
  File "<frozen importlib._bootstrap>", line 986, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 680, in _load_unlocked
  File "PyInstaller\loader\pyimod02_importers.py", line 419, in exec_module
  File "fire\core.py", line 67, in <module>
    from fire import formatting
  File "<frozen importlib._bootstrap>", line 1007, in _find_and_load
  File "<frozen importlib._bootstrap>", line 986, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 680, in _load_unlocked
  File "PyInstaller\loader\pyimod02_importers.py", line 419, in exec_module
  File "fire\formatting.py", line 21, in <module>
    from fire import formatting_windows  # pylint: disable=unused-import
  File "<frozen importlib._bootstrap>", line 1007, in _find_and_load
  File "<frozen importlib._bootstrap>", line 986, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 680, in _load_unlocked
  File "PyInstaller\loader\pyimod02_importers.py", line 419, in exec_module
  File "fire\formatting_windows.py", line 60, in <module>
    initialize_or_disable()
  File "fire\formatting_windows.py", line 38, in initialize_or_disable
    if sys.stdout.isatty() and platform.release() == '10':
AttributeError: 'NoneType' object has no attribute 'isatty'

The Fire code in "formatting_windows.py" invoques an "isatty()" function that does not exists in "sys.stdout" in Python 3.9.

if sys.stdout.isatty() and platform.release() == '10':

To resolve the release, I check if the "isatty" member exists in the "sys.stdout" object.

if hasattr(sys.stdout, "isatty") and sys.stdout.isatty() and platform.release() == '10':

IMPORTANT

1. The error doent occur in all version of Python and I dont no why, but in "Python 3.9.2rc1" it does.
2. The error does not say null anywhere, it says the attribute isatty was not found in function
3. I found this same error in other cases on Google.

[dbieber]

Thanks for the PR!