Fix typing issues

Author: dolfies

discord/channel.py

@@ -103,7 +103,7 @@
     from .sticker import GuildSticker, StickerItem
     from .file import File
     from .user import BaseUser, ClientUser, User
-    from .guild import Guild, GuildChannel as GuildChannelType
+    from .guild import Guild, GuildChannel as GuildChannelType, UserGuild
     from .settings import ChannelSettings
     from .read_state import ReadState
     from .types.channel import (
@@ -4653,7 +4653,7 @@ async def _get_channel(self) -> PartialMessageable:
         return self
 
     @classmethod
-    def _from_webhook_channel(cls, guild: Guild, channel: WebhookChannelPayload) -> Self:
+    def _from_webhook_channel(cls, guild: Union[Guild, UserGuild], channel: WebhookChannelPayload) -> Self:
         return cls(
             state=guild._state,
             id=int(channel['id']),

discord/message.py

@@ -446,11 +446,11 @@ async def to_file(
     def to_dict(self) -> AttachmentPayload:
         result: AttachmentPayload = {
             'filename': self.filename,
+            'flags': self._flags,
             'id': self.id,
             'proxy_url': self.proxy_url,
             'size': self.size,
             'url': self.url,
-            'spoiler': self.is_spoiler(),
         }
         if self.height:
             result['height'] = self.height
@@ -460,6 +460,8 @@ def to_dict(self) -> AttachmentPayload:
             result['content_type'] = self.content_type
         if self.description is not None:
             result['description'] = self.description
+        if self.title is not None:
+            result['title'] = self.title
         return result