[lint] Fix types used for __slots__ and __all__

Stay consistent with the rest of the library and use lists for module
__all__ values and tuples for class __slots__ attributes.

discord/activity.py

@@ -28,7 +28,7 @@ from .enums import ActivityType, try_enum
 from .colour import Colour
 import datetime
 
-__all__ = ('Activity', 'Streaming', 'Game', 'Spotify')
+__all__ = ['Activity', 'Streaming', 'Game', 'Spotify']
 
 """If curious, this is the current schema for an activity.
 

discord/channel.py

@@ -36,7 +36,7 @@ import discord.abc
 import time
 import asyncio
 
-__all__ = ('TextChannel', 'VoiceChannel', 'DMChannel', 'CategoryChannel', 'GroupChannel', '_channel_factory')
+__all__ = ['TextChannel', 'VoiceChannel', 'DMChannel', 'CategoryChannel', 'GroupChannel', '_channel_factory']
 
 async def _single_delete_strategy(messages):
     for m in messages:

discord/user.py

@@ -466,7 +466,7 @@ class User(BaseUser, discord.abc.Messageable):
         Specifies if the user is a bot account.
     """
 
-    __slots__ = ('__weakref__')
+    __slots__ = ('__weakref__',)
 
     def __repr__(self):
         return '<User id={0.id} name={0.name!r} discriminator={0.discriminator!r} bot={0.bot}>'.format(self)

discord/webhook.py

@@ -34,7 +34,7 @@ from . import utils
 from .errors import InvalidArgument, HTTPException, Forbidden, NotFound
 from .user import BaseUser, User
 
-__all__ = ('WebhookAdapter', 'AsyncWebhookAdapter', 'RequestsWebhookAdapter', 'Webhook')
+__all__ = ['WebhookAdapter', 'AsyncWebhookAdapter', 'RequestsWebhookAdapter', 'Webhook']
 
 class WebhookAdapter:
     """Base class for all webhook adapters.