Allow pins events to work with threads

discord/state.py

@@ -1249,7 +1249,7 @@ class ConnectionState:
             return pm
 
         for guild in self.guilds:
-            channel = guild.get_channel(id)
+            channel = guild.get_channel(id) or guild.get_thread(id)
             if channel is not None:
                 return channel
 

docs/api.rst

@@ -654,7 +654,7 @@ to handle it, which defaults to print a traceback and ignoring the exception.
     This requires :attr:`Intents.guilds` to be enabled.
 
     :param channel: The guild channel that had its pins updated.
-    :type channel: :class:`abc.GuildChannel`
+    :type channel: Union[:class:`abc.GuildChannel`, :class:`Thread`]
     :param last_pin: The latest message that was pinned as an aware datetime in UTC. Could be ``None``.
     :type last_pin: Optional[:class:`datetime.datetime`]