Fix App Docs for lightning ssh-keys command (#15773)

fixed ssh-keys docs

Author: rlizzo

docs/source-app/workflows/ssh/index.rst

@@ -48,7 +48,7 @@ You can add SSH keys using Lightning.ai website (Lightning.ai > Profile > Keys)
 
 .. code:: bash
 
-   $ lightning add ssh-key --public-key ~/.ssh/id_ed25519.pub
+   $ lightning create ssh-key --public-key ~/.ssh/id_ed25519.pub
 
 You are now ready to access your Lightning Flow and Work containers.