Use typing.Self throughout library

discord/abc.py

@@ -70,6 +70,8 @@ __all__ = (
 T = TypeVar('T', bound=VoiceProtocol)
 
 if TYPE_CHECKING:
+    from typing_extensions import Self
+
     from .client import Client
     from .user import ClientUser
     from .asset import Asset
@@ -216,9 +218,6 @@ class _Overwrites:
         return self.type == 1
 
 
-GCH = TypeVar('GCH', bound='GuildChannel')
-
-
 class GuildChannel:
     """An ABC that details the common operations on a Discord guild channel.
 
@@ -817,12 +816,12 @@ class GuildChannel:
             raise TypeError('Invalid overwrite type provided.')
 
     async def _clone_impl(
-        self: GCH,
+        self,
         base_attrs: Dict[str, Any],
         *,
         name: Optional[str] = None,
         reason: Optional[str] = None,
-    ) -> GCH:
+    ) -> Self:
         base_attrs['permission_overwrites'] = [x._asdict() for x in self._overwrites]
         base_attrs['parent_id'] = self.category_id
         base_attrs['name'] = name or self.name
@@ -835,7 +834,7 @@ class GuildChannel:
         self.guild._channels[obj.id] = obj  # type: ignore - obj is a GuildChannel
         return obj
 
-    async def clone(self: GCH, *, name: Optional[str] = None, reason: Optional[str] = None) -> GCH:
+    async def clone(self, *, name: Optional[str] = None, reason: Optional[str] = None) -> Self:
         """|coro|
 
         Clones this channel. This creates a channel with the same properties