Check that the id in looks_like exists

[snipercup]

Is your feature request related to a problem? Please describe.

Looks_like can have an entry that does not exist. For example I can enter "looks_like": "undefined", and the game does not complain. Right now a couple of items have looks_like 'pouch' but 'pouch' does not exist as an id. See #37759

Describe the solution you'd like

When launching the game it should throw an error (that can be ignored) if it finds a looks_like that points to an id that does not exist.

Describe alternatives you've considered

Removing the looks_like entries that do not point to an existing item

[snipercup]

Found another example where boxer_briefs was spelled as boxer-briefs. Of course while adding looks_like it should be tested properly but having the game check it for you should help. I'm finding out now becuase my cdda-content-manager only allows me to select valid ids

[mlangsdorf]

look-ups for looks_like failing silently is the correct and desired behavior. If you want to write an out-of-game JSON reference validator, that would be appreciated, but that's a separate thing.

End users shouldn't be burdened with scary debug messages every time they encounter a spelling mistake in an optional entry in new content.