Fix typo in documentation (#1091)

Author: aaqibb13

docs/client.rst

@@ -134,7 +134,7 @@ In the case of the ``asyncio`` client, the method is a coroutine::
     await sio.connect('http://localhost:5000')
 
 Upon connection, the server assigns the client a unique session identifier.
-The applicaction can find this identifier in the ``sid`` attribute::
+The application can find this identifier in the ``sid`` attribute::
 
     print('my sid is', sio.sid)