docs: remove duplicate 'on' in comment (#2370)

Remove duplicate 'on' in comment

Signed-off-by: Thomas Gassmann <[email protected]>

Author: thomasgassmann

docker/models/containers.py

@@ -670,7 +670,7 @@ def run(self, image, command=None, stdout=True, stderr=False,
             network_mode (str): One of:
 
                 - ``bridge`` Create a new network stack for the container on
-                  on the bridge network.
+                  the bridge network.
                 - ``none`` No networking for this container.
                 - ``container:<name|id>`` Reuse another container's network
                   stack.