Fix inconsistency and inaccuracy in large metal box's description

[Testudo-Cultu]

Summary

Interface "Correct the description of large metal boxes so it doesn't say the box is 'small' or 'slim' since neither of these things are true."

Purpose of change

It just fixes a trivial mistake. I'm guessing from the description that someone was planning to make a small oversized box for longer items, but decided it wasn't necessary and converted the item to a large box but forgot to change the description. Not sure why it's called a crate rather than a box, though.

Describe the solution

It would be much too complicated and require filling at least several textbooks to even convey the elementary principles

I just rewrote the description.

Describe alternatives you've considered

Doing nothing.

Testing

Didn't test, but this only changes some text. I'd have truly outdone myself if I broke anything.

Additional context

I friggin' love boxes and puttin' stuff in boxes.