Avoid explicitly passing the loop to asyncio

This behaviour is deprecated and will be removed in future versions
of Python. Technically, it could be considered a bug (invalid usage
causing different behaviour from the expected one), and in practice
it should not break much code (because .get_event_loop() would likely
be the same event loop anyway).

telethon/events/common.py

@@ -92,7 +92,7 @@ class EventBuilder(abc.ABC):
             return
 
         if not self._resolve_lock:
-            self._resolve_lock = asyncio.Lock(loop=client.loop)
+            self._resolve_lock = asyncio.Lock()
 
         async with self._resolve_lock:
             if not self.resolved: