Fix typing issues and improve typing completeness across the library

Co-authored-by: Danny <Rapptz@users.noreply.github.com>
Co-authored-by: Josh <josh.ja.butt@gmail.com>

discord/gateway.py

@@ -54,6 +54,8 @@ __all__ = (
 )
 
 if TYPE_CHECKING:
+    from typing_extensions import Self
+
     from .client import Client
     from .state import ConnectionState
     from .voice_client import VoiceClient
@@ -62,10 +64,10 @@ if TYPE_CHECKING:
 class ReconnectWebSocket(Exception):
     """Signals to safely reconnect the websocket."""
 
-    def __init__(self, shard_id, *, resume=True):
-        self.shard_id = shard_id
-        self.resume = resume
-        self.op = 'RESUME' if resume else 'IDENTIFY'
+    def __init__(self, shard_id: Optional[int], *, resume: bool = True) -> None:
+        self.shard_id: Optional[int] = shard_id
+        self.resume: bool = resume
+        self.op: str = 'RESUME' if resume else 'IDENTIFY'
 
 
 class WebSocketClosure(Exception):
@@ -225,7 +227,7 @@ class VoiceKeepAliveHandler(KeepAliveHandler):
         ack_time = time.perf_counter()
         self._last_ack = ack_time
         self._last_recv = ack_time
-        self.latency = ack_time - self._last_send
+        self.latency: float = ack_time - self._last_send
         self.recent_ack_latencies.append(self.latency)
 
 
@@ -339,7 +341,7 @@ class DiscordWebSocket:
 
     @classmethod
     async def from_client(
-        cls: Type[DWS],
+        cls,
         client: Client,
         *,
         initial: bool = False,
@@ -348,7 +350,7 @@ class DiscordWebSocket:
         session: Optional[str] = None,
         sequence: Optional[int] = None,
         resume: bool = False,
-    ) -> DWS:
+    ) -> Self:
         """Creates a main websocket for Discord from a :class:`Client`.
 
         This is for internal use only.
@@ -821,11 +823,11 @@ class DiscordVoiceWebSocket:
         *,
         hook: Optional[Callable[..., Coroutine[Any, Any, Any]]] = None,
     ) -> None:
-        self.ws = socket
-        self.loop = loop
-        self._keep_alive = None
-        self._close_code = None
-        self.secret_key = None
+        self.ws: aiohttp.ClientWebSocketResponse = socket
+        self.loop: asyncio.AbstractEventLoop = loop
+        self._keep_alive: Optional[VoiceKeepAliveHandler] = None
+        self._close_code: Optional[int] = None
+        self.secret_key: Optional[str] = None
         if hook:
             self._hook = hook  # type: ignore - type-checker doesn't like overriding methods
 
@@ -864,7 +866,9 @@ class DiscordVoiceWebSocket:
         await self.send_as_json(payload)
 
     @classmethod
-    async def from_client(cls: Type[DVWS], client: VoiceClient, *, resume=False, hook=None) -> DVWS:
+    async def from_client(
+        cls, client: VoiceClient, *, resume: bool = False, hook: Optional[Callable[..., Coroutine[Any, Any, Any]]] = None
+    ) -> Self:
         """Creates a voice websocket for the :class:`VoiceClient`."""
         gateway = 'wss://' + client.endpoint + '/?v=4'
         http = client._state.http