Update first_config.rst to fix invalid inspect command

[xsalazar]

Remove invalid CLI args in example

As far as I can tell from the --help reference on inspect (and the fact that I couldn't get this to work 😅), I don't think specifying the config path in the inspect command is valid?

---

usage: ytdl-sub inspect [-h] [-l 0,1,2,3] [-m MATCH [MATCH ...]] [-o DL_OVERRIDE] [-k VAR=VALUE] [SUBPATH ...]

positional arguments:
  SUBPATH               path to subscription files, uses subscriptions.yaml if not provided

options:
  -h, --help            show this help message and exit
  -l 0,1,2,3, --level 0,1,2,3
                        level of inspection to perform:
                            0 - original   present the subscription as-is
                            1 - fill       fill in defined values
                            2 - resolve    resolve all possible variables (default)
                            3 - internal   resolve all variables to their internal representation
                            
  -m MATCH [MATCH ...], --match MATCH [MATCH ...]
                        match subscription names to one or more substrings, and only run those subscriptions
  -o DL_OVERRIDE, --dl-override DL_OVERRIDE
                        override all subscription config values using `dl` syntax, i.e. --dl-override='--ytdl_options.max_downloads 3'
  -k VAR=VALUE, --mock VAR=VALUE
                        ability to mock one or more variable values, i.e. --mock 'title=Lets Play'