Incorrect syntax in Read the Docs

[ztephm]

From a Support client:

In this page https://carto-python.readthedocs.io/en/latest/auth_api.html#revoke-access-to-your-account-to-an-api-key
we should change
api_key_mamager = APIKeyManager(auth_client)
to
api_key_manager = APIKeyManager(auth_client)