docs: guild.owner_id type mismatch between docs and code (#1273)

Author: nerd-bear

disnake/guild.py

@@ -177,8 +177,9 @@ class Guild(Hashable):
         The channel that denotes the AFK channel. ``None`` if it doesn't exist.
     id: :class:`int`
         The guild's ID.
-    owner_id: :class:`int`
+    owner_id: Optional[:class:`int`]
         The guild owner's ID. Use :attr:`Guild.owner` if you need a :class:`Member` object instead.
+        This may be ``None`` if the guild is :attr:`~Guild.unavailable`.
     unavailable: :class:`bool`
         Whether the guild is unavailable. If this is ``True`` then the
         reliability of other attributes outside of :attr:`Guild.id` is slim and they might