Fix typos in comments

- "menthods" -> "methods" in datastructures.py
- "excuting" -> "executing" in asyncio/connection.py

Author: maxtaran2010

src/websockets/asyncio/connection.py

@@ -823,7 +823,7 @@ async def keepalive(self) -> None:
                 # closing because ping(), via send_context(), waits for the
                 # connection to be closed before raising ConnectionClosed.
                 # However, connection_lost() cancels keepalive_task before
-                # it gets a chance to resume excuting.
+                # it gets a chance to resume executing.
                 pong_received = await self.ping()
                 if self.debug:
                     self.logger.debug("% sent keepalive ping")

src/websockets/datastructures.py

@@ -165,7 +165,7 @@ def raw_items(self) -> Iterator[tuple[str, str]]:
         """
         return iter(self._list)
 
-    # Internal menthods
+    # Internal methods
 
     def set_insecure(self, key: str, value: str) -> None:
         """