fix bad string formatting in states.nftables comment messages
fix bad string formatting in states.nftables comment messages

************* Module salt.states.nftables
salt/states/nftables.py:415: [E1306(too-few-format-args), delete] Not enough arguments for format string
salt/states/nftables.py:462: [E1306(too-few-format-args), flush] Not enough arguments for format string

saltstack/salt,saltstack/salt,saltstack/salt,saltstack/salt,saltstack/salt