Fix typo

Author: bjoernricks

gvm/protocols/core/_connection.py

@@ -184,7 +184,7 @@ def receive_data(self, data: bytes) -> Optional[Response]:
 
         Raises:
             An InvalidStateError if no data can be received currently. For
-            example if not request is send yet.
+            example if no request is send yet.
         """
         return self._state.receive_data(data)