chore: fix return type docs for container.logs() (#2240)

Author: BobDu

docker/api/container.py

@@ -844,7 +844,7 @@ def logs(self, container, stdout=True, stderr=True, stream=False,
                 float (in fractional seconds)
 
         Returns:
-            (generator or str)
+            (generator of bytes or bytes)
 
         Raises:
             :py:class:`docker.errors.APIError`

docker/models/containers.py

@@ -313,7 +313,7 @@ def logs(self, **kwargs):
                 float (in nanoseconds)
 
         Returns:
-            (generator or str): Logs from the container.
+            (generator of bytes or bytes): Logs from the container.
 
         Raises:
             :py:class:`docker.errors.APIError`