Burning
Burning an asset means to destroy an asset that a contract has minted.
The standard library contains a module that can be used to burn an asset.
There is one function used to burn:
To use the function we must import it.
use std::asset::burn;
burn
To burn some amount of an asset we specify the amount that we would like to burn and pass it into the burn() function.
    let amount = 10;
    burn(SubId::zero(), amount);