`db inspect` doesn't accept ancient flag

[lightclient]

System information

Geth version: 1.10.13-unstable (e761255)

Expected behaviour

Show db inspect output.

Actual behaviour

Fails to accept database.ancient flag.

Steps to reproduce the behaviour

$ geth db inspect --datadir=/chain/fast/geth-mainnet
Fatal: Could not open database: ancient chain segments already extracted, please set --datadir.ancient to the correct path

$ geth db inspect --datadir=/chain/fast/geth-mainnet --datadir.ancient=/chain/
ancient/geth-mainnet
Incorrect Usage: flag provided but not defined: -datadir.ancient