Reformat code using black

Segments where readability was hampered were fixed by appropriate
format skipping directives. New code should hopefully be black
compatible. The moment they remove the -S option is probably the moment
I stop using black though.

discord/file.py

@@ -28,9 +28,11 @@ from typing import Any, Dict, Optional, Union
 import os
 import io
 
+# fmt: off
 __all__ = (
     'File',
 )
+# fmt: on
 
 
 class File: