[docs][4.14.0+] Sphinx possibly misconfigured @ CLI interface page in docs

## Issue

I was browsing the docs and noticed this thing:
```
config file ‘/home/docs/.config/tox/config.ini’ missing (change via env var TOX_USER_CONFIG_FILE)
```

It's at the very bottom of https://tox.wiki/en/4.14.0/cli_interface.html.

## Environment

RTD, the first version that has it is v4.14.0. Older docs versions don't have this string printed out.